A few seconds ago the History Channel had a show on about the the Hoover Dam. Right on the retaining wall of the dam was stenciled “Danger, Keep Off Wall”. I was struck by the fact that this warning was needed. If anybody was boneheaded enough to look over that edge, then get up on that wall, then maybe humanity would be better off without their contribution to the gene pool.
Unless it’s there for workers.
more likely, it’s there for the lawyers.
Yeah, point well taken, but water is scarce in the region.
…and nobody wants to drink dumbass on the rocks.
Somewhere I have a pic of my son and his cousins way past the warning sign on the side of Pike’s Peak. They decided to see how far they could climb down the steep side. They got stuck, and took them a while to figure out how to get back up. They were obedient children after that for about half an hour until the scare wore off.
If you take the Hoover Dam tour, there’s a place on the inside, about halfway up from the bottom on the downriver side, where you can stick your arm out an opening and wave. It will freak out anyone on top who happens to see it. 
As some of you may know, I used to work in a prison.
We had to allow prisoners access to razors so they could shave. But at the same time, we had to have a system in place on keeping track of the razors so they wouldn’t turn them inot weapons. And we had to have a system of safely disposing of the used razors.
We came up with a cheap disposal system of using plastic jugs (which we got for cleaning supplies). We’d cut a flap in the top. The prisoner would give his used razor to the guard, who would check to make sure the blade was still in it and then push the razor in through the flap. The razors would stay in the jug without falling out and when it was full, we’d throw out the whole jug.
But one guard, on his own, decided to add an extra step. After collecting the razors, he would snap them in half, breaking the head off from the stem, before putting the pieces in the jug. He had apparently been doing this for a while when his hand slipped one day and he cut his hand with the razor.
So we had a big meeting with all of us boss types where we discussed the policy. How should we change it to avoid a repeat of this problem. People were suggesting issuing a set of written instructions on how to dipose of razors safely and working on the wording.
And I said, “I don’t think we need a written policy. I’m sorry he cut himself, but let’s face it, the guy was stupid. Nobody told him to break the razor blades in half and there was no reason to do it. Everyone else figured out on their own that you shouldn’t play with razor blades. Why should we make up a written policy for everyone because we have one idiot? Are we going to write a policy telling people they shouldn’t drink bleach or stick their keys in electric outlets or eat the glass from a broken lightbulb? Some things should be obvious.”
I’ve wondered about stuff like that in the past, too. We have an overpass here that has a sign on saying, “Do Not Jump Over Handrail.” Well, no shit, eh? Maybe it’s there to prevent people from falling on the cars driving below.
I was recently on a ferry that had a sign at the very back of the boat that said “no passengers beyond this point”. Totally spoiled my plan to barefoot waterski from Key West to Ft. Myers. 
So what happened?
Recent events in my preschool class have led me to consider a “Do not eat the sand” sign. You would think trying it once would be its own lesson, but we have at least one repeat offender.