How to determine whether a 10 days S.N. Goenka Vipassana course is safe for my friend or relative?

What approach should be taken while deciding whether to go on a course or not, or whether to encourage someone to go on a course?

To the first question, to go or not to go is a personal decision. Some may find little investigation in advance is necessary while others may need or desire awareness sufficient to overcome fears, uncertainty, or doubt. Others still may simply need enough facts to weigh cost/benefit or risk/reward. These value judgments are ultimately the responsibility of the interested person.

You may share your experience, strength, and hope with those that welcome such. After which, your duty is exhausted.

You may also share your fears, uncertainty, and doubt with others, if such is welcomed. However, ultimately the choice to act or not to act is upon them. And subsequently, their experience is their experience.

To all those for whom you are not a teacher (that have not inquired or welcomed your guidance), you are imposing your values upon them. Such an act is proselytizing and the subject to an entirely different question.

To the title question...

How to determine whether a 10 days S.N. Goenka Vipassana course is safe for my friend or relative?

Beyond sharing your own experience, strength, and hope... the duty is upon your friend or relative to determine safety. Without being pedantic, safety in this context is ill-defined. Appropriateness is probably a better word and still the burden is upon them -- not you.

That the experiences of others is not aligned with your experience and your desire to confront those differences is a teaching moment for you.

What is the nature of the craving you feel to reconcile the differences in experience? Is such a craving rooted in the safety of your family or friends... or in yourself?

Your best service to others is to deeply internalize good practice, model good practice, be good practice. You can only live your life. Channel the passion and enthusiasm you have discovered into enhancing the integrity of your practice and step away from the desire, clinging, and attachment you have toward the practice of others.

First of all congratulations for having a good meditation experience, seeing the Dharma of ending suffering isn't easy to come by.

This is one of the reason why Right Concentration is the very last on the Eightfold Noble Path. Without the other supporting factors, meditation isn't going be very effective.

I have had some experience with meditation retreats as well as monastic retreats as a novice monk, and generally the first thing we will come across during the meditation is sheer mental suffering from the withdrawal of all the pleasures we used to cope - burying our mental afflictions with them. Whether it's social media, gaming, drinking or sex. If your friends and family were expecting it to be peaceful and pleasant, they might be in for a nasty surprise.

Worse still, if they have been violating the Precepts and not acting ethically through their words and deeds, it's likely to come up to haunt them. This might not necessarily be a bad thing from a self realization perspective. But they might have to get past some nasty experiences. I heard stories about butchers and murderers coming face to face with the realization of the harm they have done to others.

Further more, due to the sensory deprivations, the mind can start to hallucinate by fabricating its own sensory experiences, if we had the wrong view and wrong intentions, we could start deluding ourselves, or start having some terrifying hallucination.

The goal of meditation is to calm the mind enough so that we could start letting go of the afflictions. If we aren't sure what we are doing, we could be just sitting there hating every minute of it and fabricating more afflictions.

This is why it is necessary in the Buddhist path to create sufficient merits, practice good ethics in our life, be mindful of our thoughts, words and actions, and work hard at it before meditation will be effective.

Successfully passing through the suffering do lead you to happy blissful, peaceful and clear meditative states known as the Jhanas though! Well done!

I have recently participated in a 10 days S.N. Goenka Vipassna course, which had incredible positive results... My life has improved significantly in each and every aspect, and I was even able to bring positive awareness to the lives of my beloved ones.

Obviously, the retreat & practise was suitable for your individual disposition but this does not apply to everyone.

Naturally I want everyone to participate in a course immediately, especially people I am close to, and especially those who are in great suffering.

This is wrong understanding because meditation does not benefit everyone. The Buddhist scriptures refer to those that benefit from Buddhism as relatively "few".

174. Blind is the world; here only a few possess insight. Only a few, like birds escaping from the net, go to realms of bliss.

Dhammapada

If I have the power to influence someone to acquire this amazing tool in a healthy manner

My personal experience of Buddhism followed established Buddhist principles, namely, I myself was searching for something when I found Buddhism. Similarly, others are expected to take their own first steps when searching for solutions.

Buddhist principles do not support proselytization. The suttas state:

This is the best of gifts: the gift of Dhamma. And this is the best of friendly speech: to teach again and again Dhamma to those who wish for it and who listen attentively.

AN 9.5

I can see that you are feeling a bit evangelical after the Goenka Retreat, and you have a great desire to tell others about it. What you are trying to give is a “Dhamma Dana” is Pali for “The Gift of Dhamma.” It is the best gift you can give, this gift of Dhamma. So to your question:
What approach should be taken to encourage someone to go on a course?

The short answer is… there is a right time and a place for it, and you will have ‘to let go’ of this desire to tell others about it. When we feel enthusiastic we begin to impose our enthusiasms on other people. But when it come to this Ten Day Goenka Meditation, you may have to let go of your desire to influence others UNTIL the right time comes. Then it happens naturally rather than as an aggressive action. There is a level of readiness that comes in stages. There is the Pre-contemplation stage, then the Contemplation stage. Then in the Preparation stage, one has to read about Goenka and the Program & get to know of it beforehand. Then only would come the Action – “The time is Now” moment.

I don't think they are safe for anyone. It's a very ascetic style of retreat and in my opinion not healthy for body or mind. I know someone who was dragged from the room kicking and screaming. Its not good for the lay person to sit there for ten hours at a time. The body does not cope. Combine that with sleep deprivation because of crowded dorm style accommodation and also having to listen to the grating voice of goenka ad nauseam on the videos they use. It's enough to drive anyone over the edge. There are many more much gentler, less strict forms of meditation and retreats so I'm unsure why anyone would put themselves through that torture. Doesn't seem very kind or compassionate to me. You could suggest to your friend to look into doing an insight retreat in the tradition of Mahasi Sayadaw. The sitting is combined with walking. It's much better and they have actual teachers guiding and not just a video like at Goenka so you can communicate and ask questions about your practice. I love them.

I would suggest that you trust yourself to make that decision for each individual you are contemplating the recommendation.

You have personally taken the course so you have firsthand knowledge of its contents and rigors. The people you are going to be talking with are 'close' by your description so you already know a lot about who they are and should understand (or be able to learn through discussion) approximately where each one is on their personal journey on the path toward Enlightenment - and what help they might need.

With those pieces of knowledge, and the additional understanding of the issues others have had with the course (references you provided in your question), you are in a good position to analyze the issues for each and make that decision.

For those you decide to approach, I would make sure to spend the time informing them not only about the benefits you obtained but also some about the potential negatives that others have had. In this way, they will have all of the information they will need to look within themselves and decide if this is right for them.

In my opinion, withholding knowledge of training which you feel could help another would be as bad as blithely recommending it without providing the understanding of the possible difficulties they might encounter.

Through using your judgement and taking the middle path, I believe you will have done your best to assist all of them on their journey.

All these episodes are you past Karma or Fabrications in many cases. Sometimes meditation might coincide with the time they were supposed to manifest themselves. With 100k+ or more people doing a retreat every year in 200+ centres there can be such cases. So there is always a chance some independent events happening and someone inferring a correlation between the two.

Some time it might be the meditation which triggers the past Karma or fabrication coming up.

Let me change the argument for a little. Say you went to a beautiful park. You enjoyed it. You want a friend to enjoy the scene and tranquility. Now you learn that someone visiting the park was knocked down on the way. Should this stop you from recommending the part to someone else. Also investigating more you read someone playing with fireworks at the park was hurt. Should you be more worried. They are either coincidental, or negligence, in many cases.

When you do recommend the course of course you should warn the friend that this involved working at a deep level of the mind and you should be cautious. You should stick to the instructions meticulously. Think ong it as you are operating on yourself. If you are doing this you have to be careful.

Key point to remember is:

• whatever experience, be equanimous knowing it's impermanence, if you are not, then you are creating unwholesome roots which can have undesirable results
• whatever the experience, do not try to give more meaning to it that what is experienced, since your mind has Vipallasa (see: Vipallasa Sutta), it will most likely give a wrong identification and / or wrong view
• when you go do not go with expectations, as this will result in disappointment and disturb the balance of your mind. Excessive craving for results. My headache is still not gone after meditation for x days.

If you look at the instruction, something can go wrong if the instructions create unwholesome states. Being equanimous and seeing impermanence you abandon unwholesome states. (See: Pahāna Sutta for further information.) Also you do not use any visualisation, verbalisation, imagination which abandones verbal fabrications which are not in touch with the ultimate reality hence unwholesome (there will be at least dilution present). Also abandoning verbal fabrications reinforces concentration as your mind becomes less scattered. Also you practice Samadhi which is mastery over the mind which is wholesome as well as morality which is wholesome.