I might be heartless, who knows, but if i ran a liquor store unless people were making a nuisance in my store i wouldn't care. If they were intoxicated when buying the alcohol yeah i would refuse. But it's no ones business other then the people who paid for the goods what happens when they leave.
Imagine a check out person denying teenagers condoms because they don't believe in teenage/premarital sex.
It's no ones business (unless they feel something illegal is happening)