As for the receipt check "policy", it's just that, a store policy not a state or federal law. She had every right to go out another exit or go around the receipt check line and walk out the door. If in a hurry, I would have done the same thing, just like I will not stop if I set of the door alarm at Wal-Mart because the stupid cashier forgot to disable the security tag on one of products. A couple times somebody has followed me out, at which time I will show them my receipt, most of the time they will ignore it. But it is not my responsibility to stop because a beep goes off when I walk out the door.
Either my keys or my cell phone always sets off embarrassingly loud alarms in our local mall stores. I feel like people glare at me like I’m a criminal. I go to the nearest clerk and explain myself. Sure wastes a lot of time.