it's a continuous cost-benefit optimization.

if it would be cheaper to clean beaches we would just do that. if it would be cheaper to put some manners into beachgoers, we would do that. if it would be cheaper to "police" beaches, we would do that too.

regulations also have costs, such as annoyance, inconvenience, enforcement, etc.

we will see how these will turn out culturally. (as in which "external rules" will turn into internal ones.)