Nope, I don't advertise. I've heard too many tales of people's cars getting broken in to for thieves to rummage through looking for guns, gear or what have you. I also don't advertise on our house for the same reason that I spend a minute or so peeking out the windows before hauling guns to the car for a range trip. No need for neighbors, traffic, etc. to have any idea of what I do or do not have. Aside from the possible MWAG call, I don't want the unscrupulous sort to start casing our place waiting for an opportunity to steal possibly expensive goodies.
The closest I've got was a "God Bless Our Troops, Especially The Snipers" sticking on a vehicle.