Sneaking Out Free Food
Here’s the thing about buffets. While you’re in there, you’re allowed to eat as much as you can. It’s only after you eat more than the reasonable amount of five people that a restaurant can and will stop serving you, but that’s usually only for that night. More often than not, you’re welcome to come back on another day.
What you’re not allowed to do is sneak food out of the restaurant. They already gave you the go-ahead to eat as much as your stomach can hold. Why go through the trouble of sneaking food out? According to the OP, their may-or-may-not-be-their-mom did it for the excitement.