Drug Free School Zones?

What's the deal with some signs?

Most signs have a directly discernible intent, whether it be to advertise a business, or inform a driver, or give direction.

There are some signs though, that I'm not really sure about. I see one of them around quite a bit. It's the "Drug Free School Zone" sign. You've seen it. (here's an iStockphoto of one)

I don't really understand this.

Who is this for? What's the purpose of such a sign? Is it true?

If this is meant to be a statement of location or condition, akin to "This is the Santa Fe Trail" then how do I even believe it? Is this school zone really drug free? How do they know that it's true? Do they regularly do drug screenings? Go house to house and make sure everyone is clean? Just putting up a sign doesn't make it so.

And who is this for anyway? Passers by, homeowners, school kids...drug dealers? Assuming that the function of a sign is to inform, it's hard to know just who the audience for this one is.

In terms of supply and demand, this could be an advertisement for nefarious characters. "Hey, we've got no drugs here in this area... the market is wide open for you, the drug dealer looking to expand your market, and there's no competition here yet - hence the sign ... welcome!"

Wouldn't it be more effective and honest if there were a sign like "increased drug law enforcment area" or "drug related offenses doubled" or something. It's the drug free part that seems silly to me. The sign just sits, whether a drug deal is happening right there or not.

If it's talking about a law - well, in terms of illicit and illegal drugs, aren't all zones of the US supposed to be drug free? (Unless, perhaps, you're a peyote toting Native American) This sign doesn't really create or inform of any special laws that I'm aware of. Why create a sign like this? It's not like there are signs for "Drugs OK School Zone." Like designated smoking location. This is a Dooby Do Zone. Go ahead, pot head. Mmm-no.

So, I don't get it. It's it just wishful thinking? Saying something in the hopes that it will self-produce that happy state? Not sure.

Just a small question. One of those things around that I don't really understand, but thought it would be nice to not understand it together. Not that anyone is reading this.