Alcohol, 21, and Carding. Okay this is a weird question but I've always wondered what the deal is. If you go into a supermarket and grab some beers and a bottle of liquor or something and they card you but you are with a buddy that is under 21, will they card him/her too? What happens whhen they find out he/she isn't 21? Do you both get in trouble? Do they call the cops? Do they assume you are buying it for them? Will they just not let you buy it? Or do they have to since one of you is 21?