IWonder, you have a nice theory, and it works just fine for people like me, who can keep a cushion of cash in their checking accounts without going hungry. But the person I was speaking to is apparently trying to live on disability payments (massive physical injury), and she is apparently trusting enough to believe that when the bank's telephone system says she still has $20 in her account at three in the afternoon, and she knows that she hasn't bought anything for a couple of days, that it means a $1 transaction won't result in 'bounced check' charges just four hours later.

Personally, I think she needs to hand over her financial transactions to a third party, but 'only about average skills keeping track of a checking account' isn't the legal standard for having a (quite costly) conservatorship appointed.