We have procedures now to have individuals declared incompetent and have guardians appointed. I agree, we don’t want the cure to be worse than the disease or to have corrupt institutions take advantage of people. Therefore, it would be best to error on the side of non-interference, which is about what we are doing now with the homeless.

I’d further suggest that only a portion of their UBI go to the institution, while the balance would be available to assist with the later transition out.

It also seems ripe for abuse. I can already see people going around declaring people "unfit" and getting a cut of their UBI from the committing institution.

What's worse, having a guardian to help you spend money or sleeping on the streets?

Yes