All the rules in the world are not worth crap unless they are enforced.
I dont agree with this sentiment. There are always those who wont give a damn, but I believe most people follow the existing rules, ie closures, single barbless hooks, retention limits, releasing foul hooked fish etc. And enforcement is already minimal at best.
If the regs changed to implement leader length restrictions or bar fishing only or whatever, I'll wager the majority of people would comply.
Herd mentality also is a big factor. If everyone is flossing and retaining snagged fish, then others will also feel comfortable doing the same. If one guy keeps a foul hooked fish amongst a group of ethically acting anglers, he's far more likely to hear about it and be encouraged to change his behavior. Self policing does occur (sometimes) within the recreational community, but needs clearly defined regs as a basis first. You have no foundation tell someone not to floss, because like it or not, it's a perfectly legal technique in all waters. But you could inform someone that their 20' leader is prohibited, if that was the regulation at the time.