My 17-year-old daughter works as a cashier at a grocery store. This weekend, a couple came in and checked out through her lane. They bought a package of steak tips, several bottles of marinade, and several cases of soda. My daughter remembered them in particular because she remembered packing the order - she wrapped the steak tips in a plastic bag, then put them in another bag, then put the bottles of marinade on top of it.
Short time later, the woman stormed back into the store and right to DD's register, claiming that the steak tips weren't in the bag when they got home, and that they had to make a special trip back to the store because of it. Later, she claimed that they "didn't even leave the store with them." (So, if they knew they weren't in the bag when they left the store, why go all the way home and then come back?) DD said that she then recalled that they had bought a lot more marinade than they would ever have needed for the amount of meat they had.
Obviously, they made their purchase, went home and put the steak tips in the refrigerator (or whatever) then went back and tried to scam a second package of meat.
Nice try, but it didn't work.