@Softy1 of course that would be illegal, but I don't know that I believe posing as an employee anywhere is illegal in and of itself. Not carding and handing to minors, of course is illegal. If she stole the booze, definitely illegal. But pretending to be an employee? I doubt it.
@Strictmichael75 but is posing as an employee illegal? Won't the cops just kick your off the property at most? Someone else said she prob wasnt IDing people, which is definitely a gray area unless you're only handing out shots to the silver foxes.
IF she explained it was Tecquila FIRST, she would not be endangering anyone. Lots of elderly people and OTHER people taking some medications would have a major reaction.
BUT it's not legal to hand out booze in Costco while masquerading as a sample lady without PERMISSION from the store.