I know the receipt check is on the contact, but if I just told them no there is nothing they could do, short of revoking my membership.
Last I read the terms of membership (I hesitate to call it a contract) it reads something like
"We will ask you for your receipt at the door".
They sure do ask!
IANAL, but once you pay for stuff, it's yours. For them to prove shoplifting they have to see you select the merchandise then keep eyeballs on you the entire time between then, the cashier where you pay (or don't) and then walk out the door.
If they set their store up poorly and you have to walk 50 yards between paying for your stuff and leaving the exit, why is this on you?
Also, liquor, prescriptions, eyeglasses, do not require a membership at all. Then you do not have ANY obligation to prove ownership to the door bouncer.