I don’t feel sorry for this woman, and I don’t blame the manager. If she is going to be piggish and can’t wait a few minutes and eat the sandwich after it’s been purchased, then it is her responsibility alone to make sure it gets scanned at the register. Wait next time, ditz.
One of them should have dashed, probably with the kid, to actually buy the sandwiches, while the other one shopped.
Very simple.