This article describes 2 Dominos employees who ran the famous "coupon scam."
Basically the phone person takes the order. The driver delivers the order. The customer pays full price. But the driver discounts the order with a coupon, and the driver pockets the difference. In this case it seems the phone person and the driver were in on the scam together.
Our POS system tracks "surprise coupons", or any discount added to the order after the order is initially entered, so it would be pretty difficult to try this at our store.
Plus, as I always say, the money is too good as is for me to try something like this. Not to mention it's illegal!