If this is the behaviour of people in a community, it seems absolutely necessary to institute top-down rules on which materials are permissible and which not.
That is to say, the problem here lies mainly with the attitudes and behaviour of people in this community than with specific policies.
Beaches are tourist attractions, at least in my experience during beach season, tourists outnumber locals by an order of magnitude, and locals elect to go when they aren't so crowded.
People are entitled and lazy. I’ve seen many locals litter, especially dog poo, but the majority outside my house is from the temporary sleepers whether tourists or van lifers. Substance users are the worst offenders - I pickup so many cigarette / joint butts and beer cans.
But like do tourists even have a community ? I don't think you are making sense here. Tourists are from everywhere, every one of them think the problem is the other tourists.
I really do wish people treat these places like their home. However, even people in my immediate circle, are just expecting other people to clean up for them when they're on vacation :). I don't know, something about traveling just turn on switch.
That is to say, the problem here lies mainly with the attitudes and behaviour of people in this community than with specific policies.