i did something of the same nature with making my own signs, but for different reasons.

i used to live in a very touristy part of iowa (yeah we get tourists in iowa, dumbass tourists, LOL) As a local and trying to deal with 1685547464684668465216471665 people who DON'T know where they are going, i got fed up and took window chalk and wrote all over my van.

"Grumpy Local, get out of my way!"
"If it is tourist season, why cant we shoot them?"
"Learn how to drive, or go home!"

I got passed by some local cops when i was on my way to work and i saw them laughing and they gave me a thumbs up And a few other locals would stop and say something like they were glad that someone was ballsy enough to say something. LOL i wasn't ballsy, just pissy