How come teenagers get away with drinking and don't get in trouble with the law?

On tv i see teenagers getting drinks. In nyc prep the kid pc is getting drinks when he goes out to dinner and he is 18 and on tv!How come teenagers get away with drinking and don't get in trouble with the law?
The kids won't likely get in trouble anyway, slap on the hand at most. But the company and bar tenders can for serving them if they get caught. On shows like that you don't (typically) see the kids being served, more than likely an agreement between the bar owner and camera crew/production company. Probably an agreement stating ';follow the kids, but leave employees out of it.'; Something along those lines I'm guessing.How come teenagers get away with drinking and don't get in trouble with the law?
Those aren't actual alcoholic drinks, dear, it's just staged. (That man you saw flying around in the red cape isn't real either.)