If I handed you $110 to go buy $100 of drugs, then I'm still paying for the drugs. What judge would be willing to allow such a gotcha to actually pass? There would be a massive industry for legally paying for illegal things if that were the case.

Then again, the acceptability of a gotcha seems to correlate more with the amount of money spent on lawyers than on the rationality of the gotcha, so as long as they have a large enough legal department the worse they'll have is a fine that they likely already included in the cost of the attack.