This actually happened to me, I asked for a free cheeseburger with my Big Mac meal because I had student card. The guy in mc d was so stupid and had no grasp of the English language he didn't understand anything. I said I have. A student card and with a student card you can get a free cheeseburger when you buy a meal. I turn to talk to my mate and the guy says here's your food, grab the bag get in the car and open it up and there is my Big Mac meal and 3 cheeseburgers. Check receipt -only paid for the Big Mac meal, the idiot had given me three free cheeseburgers, as we pulled out the car park he ran out the door trying to stop us. Needless to say we carried on driving and I was very proud to eat all the burgers on the journey home :-)