Making fun of the car youre driving is quite common.
If your friends and coworkers call ya charlie brown and you hate your subaru- ITS THE ULIMATE!
As to that being cheesy, well I have a sense of humor, and my friends all seem to really get a hoot out of the thing already. Expression of distaste displayed on the rear window of cars isnt new, thats for sure. But at least mines ORIGINAL. I mean, its not like I went "calvin and hobbes".
There are lots of cheesy trendy lames with all kinds of crap in the back window. "salt life" is standard on every douche's jacked up truck around here.
Well, since you are going to anyhow, flame on FLAMERS!