I honestly had no idea what this sign meant, despite driving past it countless times when driving through my friend's neighborhood. I always thought it meant "Look out for Meteorites!" You've gotta give it to me though, it DOES look way more like a meteorite than an eye. In fact, I think, when informed that it was a Neighborhood Watch sign, I actually said, "What do meteorites have to do with crime?"
I like to imagine it being left over from the Cretaceous Period. If only they had had a Meteorite watch... if only.