Upvote:1
Bank statements aren't just about whether you have enough cash on hand right now to afford the trip.
That is certainly part of it, but the bigger part is to build up a picture of the person's life. Is the cost of the visit proportional to the persons overall wealth/income? Is the persons current life in their home country better than the life of an illegal immigrant in the UK?
Immigration control is fundamentally an imperfect process. There will be legtimatite visitors who get denied and there will be people who get through immigration control and then go on to immigrate illegally, work illegally or just plain find themselves unable to afford to travel home.
Clearly a persons situation may have changed between two trips so that they present a higher risk on the second visit than on previous visits. The question a government needs to ask themselves is whether the risk of that happening is worth the costs of forcing people to get a seperate visa for each trip.