As a former manager of a restaurant, and having worked in restaurants since I was 14, I've noticed something that people should be aware of when it comes to paying for your meals at restaurants with buffets.
Ever Been to a chain restaurant with a buffet? I guarantee you they have a cashier at the front door. And Here is the reason why they don't let servers have their own banks for buffets.
Lets say a Server has 2 tables, both of them with 2 people and everyone orders the buffet. Obviously the server doesn't have to ring in a ticket since the kitchen doesn't have to actually make their food, so the server waits until the guests are about to leave to ring in their ticket. Rings up the first couple, they pay with cash, server pockets the money, doesn't ring in another ticket, and just brings the old ticket to the second table.
Lesson, When dining out at a buffet and the server is your cashier, pay with a credit card.