No, maybe he doesn’t drink next time at all because he realizes his friends aren’t supporting him. Or maybe his parents punish him when they find out and take control of the situation. It’s difficult to grasp how you can’t see that if a law-abiding friend constantly makes herself available to drive the getaway car how that encourages the illegal behavior.
Constantly? That's rather a large assumption. Obviously you never did anything you weren't supposed to as a teenager, but most everyone I ever knew in high school tried drinking at some point, sometimes to excess, which resulted in it's own punishment. All in all, I'm less concerned with that than them getting behind the wheel and killing someone else.