Can you offset against an UTMA account in a situation where the owner of the UTMA funds is the person you need to offset for?

The minor is the real "owner" of the UTMA funds. You should not offset those funds against a debt owed by the custodian. If the debt is owed by the minor, you at least have a continuity of interest between the debt you owe (deposit) and the debt you are owed. It still may not be a good idea to offset, depending on the circumstances.

I'm not an attorney, but I don't think you can offset an UTMA against a debt owed by the minor, either, because the minor does not have withdrawal rights to the UTMA account.

Thanks. That's what I thought. Just wanted a second opinion.