Pizza Hut is to remove all self-service salad carts from its 440 restaurants in China. Up to now, customers were permitted just one trip to the salad cart, but these restrictions have led to ingenious Scooby snack-style stacking of CCTV Tower proportions. The chain, the first to introduce pizza to China in 1990 and pizza delivery in 2001, claims that the move is part of a general menu expansion, but it's surely down to salad cart abuse.
Supermarkets exploit that behaviour by displaying per-person limits on merchandise. E.g. “limit 5 per person”.
It works.