I suppose the question ref. the sanction part lies in whether one is going to "bust" the watermelon by flying the airplane into the watermelon. Remember the great discussion here ref. the paintball shootouts?

That might require an electric powered airplane as it just may contaminate the melon should one use a recip. engine powered machine. Could get a bit oily, etc.

OTOH there are those that might benefit should the fuel be the old Fox Superfuel with 29% CASTOR OIL. [:-] Watermelon and Castor Oil could develop a significant shoot-out of its own kind. That might not be a covered liability under AMA's general liability policy! Lots of things to think about there!