It's bad to have sex in public.
Mark and Marcia are in love and at the crowded beach together during the day.
Mark wants to make love to his girlfriend Marcia.
Mark takes Marcia to his beachhouse and has sex with her there.
Mark starts with Marcia on the crowded beach and has sex with her in front of others.
The other beachgoers are comfortable and Mark and Marcia stay out of jail.
Other beachgoers become uncomfortable and the cops come and arrest them.