At the beaches I frequent, they have volunteers who pickup the trash left by idiots.
Early every morning these people are out as the sun is rising picking up all the trash.
Personally I think they need to try one of two things.
Either, don't pickup the trash for about two weeks to let people see what the beach would look like otherwise.
Or, pickup the trash and place it all in a big pile in the a highly visible spot to show how much crap people leave on the beach in any given summer month.
I'm afraid it probably wouldn't matter either way - Sad!!!