If the state that your in has adopted the Uniform Fiduciary Act, you may not have a lot of risk. The only problem with the UFA is that it only applies to checks. Your withdrawals would be by debit card.
I havent seen any judicial decisions that extend the protections a bank gets under the UFA when it pays a check drawn by a fiduciary to withdrawals by debit card by a fiduciary, but the logic seems sound. Why should it make a difference whether the fiduciary uses a check, debit card or withdrawal slip to access the money?
The UFA is, in principal, saying that a bank doesnt have to monitor what a fiduciary does. So, if you dont have to moitor check withdrawals, why should you have to monitor other forms of withdrawal?
Having said that, however, I would also check w/VISA to make sure it doesnt have a restriction on issuing a debit card to a fiduciary.the activity of the fiduciary.