they wont let you walk into a costco and buy a case of stella artois for $24 just like that.. you have to have membership.. you get door checked once. and carded at the register so 2 checks.. the walk out doesnt require your membership card.
most stores are famillar with the alchol policy it also applies to the pharmacy in michigan not sure of other states. If you get a cashier that knows what they are doing and not brand new they now about this however they don't always have it set up for a cashier to just handle it. This is because they need a membership to start the transaction even if it is a generic one.