Can my young cousin get in trouble for being at a party that involves alcohol?

My cousin is a freshman in college. He just turned 19. In our state, you must be 21 to purchase alcohol.

This one club at my cousin’s school is hosting a party next Saturday. Most, if not all, of the club members are at least 21 years old. Alcohol would be provided at the party, though there would be activities other than drinking available (e.g. watching a movie, eating, socializing). My cousin does not plan to drink but he wants to get to know the other members of the club better.

My cousin just met them and have no idea how they would act in a party. In the event that the neighbors call the cops (for nuisance, etc) and the cops arrive, can my cousin get in trouble for being in a party that involves alcohol even if he did not drink one drop of it?