For instance, it is illegal to throw a frisbee on a beach in Los Angeles county(1). If you are ticketed, the fine is $1,000.
Now....how many tourists going to the beach are going to know that? How many would ever bother to check? Sure, signs could help, but does everyone stop and read the 12-15 rules on any beach/pool signs?
Even more broadly, were we, as citizens with the right to free travel on public property, notified of the various laws we are subject to while passing in and out of various jurisdictions? Are we notified of the daily changes made to them? Are we given an opportunity to leave said jurisdictions when informed of laws to which we don't want to be subjected?
How are we, as citizens, supposed to understand the laws we are required to follow when we aren't directly provided with them or notified of any changes?
In the private world, there are very strict rules about this. You have to explicitly agree to terms of service before utilizing products, companies must record your agreement, and they must notify you (or provide you with a new copy) if those terms change. (The South Park episode regarding the iTunes EULA made an excellent parody of this fact).
The whole system is getting completely ridiculous and it deserves much closer attention and more publicity.
Sources:
(1): http://www.theblaze.com/stories/2012/02/09/los-angeles-oks-1...