If you are in line and the person ahead of you has the exact same $100 item but the computer accidentally rings it up as $10, do you:
A- Say nothing and hope the same thing happens to you?
B- Say something to the cashier and pay the correct amount?
C- Run out and tell all your friends that the store computer has a glitch and they can get $100 items for $10 then go back to the store over and over to get as many $100 items for $10 that you can?
Condemning people for taking an inappropriate reward that pops up in the end reward list is one thing, condemning people for taking advantage of an obviously broken mechanism is quite another.