Mah minimum wage! This is going to take off very quickly, and be very cheap without paying people to make the burgers. I see no reason though for why you wouldn't just set this up in such a way that eliminates practically ALL human interaction. Replace the server/cashier with a machine interface. Have it spit out a ticket with a barcode, and when the food is ready, the customer can scan the barcode to access their food. This is what happens when you want a minimum wage.