There is a company called “BuffetGo” that allows you to purchase leftover buffet food at a steep discount. They purchase food that remains at the end of lunch or dinner. Customers can then purchase these at steep discounts (up to 90%).
There is a small window of time at the end of lunch or dinner where customers can go to the restaurant, fill up boxes with leftover food, and take them home. Customers can only choose what’s left, not order more food.
It’s an interesting idea. I’m not sure how the restaurants deal with the legal implications of it, though.