How did Salvador Dali often get free meals at restaurants?

Dalí wasn't quite the dine and dasher, but he did cheat his way out of a few hefty restaurant bills. After hosting extravagant dinners for himself and a few friends, he would write out a cheque and then scribble a drawing on its back. As nobody wanted to pass up the chance to own a Dalí original, more often than not restaurants wouldn't cash in the cheques.