Im thinking in regards to the intent of the law - Which is to stop people from taking out payday loans and then making it so that the company cannot collect, an argument could be made for both sides. A lot of states that have laws against closing the account also allow for prosecution of stop payments too. That opens it up a bit and makes prosecution for a block not so far off . . . . .
I think it would also depend on the circumstances surrounding the situation. If there were unauthorized charges like you said in your question, I would think that you wouldn't be prosecuted, because that is not your fault. But if you managed to get a block on your account and there weren't any unauthorized charges, the block was just to keep out the payday loans, then I think an argument could be made that the intent is the same.
I'm going to make some calls today and see if I can get any other opinions . . . . .