goducks, I wish that the "lake trick" worked in California -- unfortunately, lakes are so scarce that we have more drunks than lakes. So there are plenty of dry land party people. Based just on my own experiences, the problem seems somewhat worse in areas open to off road vehicle use. I am sure that there are polite and quiet off-roaders -- but since we can't hear them, all we hear are the other ones, and they give the whole crowd a bad name, which is very unfair to the good citizens. (This is like the bad reputation given to pit bulls -- most are wonderful dogs, but a few are not, so the RV parks ban all pit bulls. But nobody bans Chihuahuas, even though they can be noisy.)
The other rule of thumb is that as you get further away from big population centers, the percentage of drunk campers decreases. That's not surprising -- even drunks know that the less they drive, the better! ;)