Upvote:3
... but are there other reasons not to pursue this strategy?
It's ethically questionable but beauty is in the eyes of the beholder. The more tangible consequence would be that the hotel becomes aware of it and just cancels all your reservations.
Could the hotel blacklist me?
They sure can. A business can freely choose who to do business with (unless they are in a protected class) and can deny you for whatever reason. In this case that's quite possible to happen.
Does the hotel have a leg to stand on it they decided to not refund my multiple deposits?
Probably not. It's more likely that they just cancel all of your reservations, refund you the money and decline any further business.