Now why didn't I think of this:

Electronic road signs are annoying. I don't have a problem with these signs warning me about road construction, except when they're left up -- flashing their stupid warnings -- well after the work is completed. Recently a construction company left a pair of these signs in my neighborhood, blasting out their pointless messages. Being a creative tinkerer, I decided to do something about it.

I know why. Because whenever I try a prank like this, without fail, it blows up in my face. Guarantee you a cop would be taking a leak in the woods behind the sign, or would be cruising for no good reason just as I was punching buttons.

With pictures!