FWIW, I wont advertise that someone is armed in my home. In my eyes, that just means a person hellbent on breaking in will be even more crazy and even more dangerous. Its the element of surprise, not the element of being obvious.
I would never let anyone know I own guns. They are (guns) just another lure for the pro burglar. It's another story if you are home, but pros wait till you are not. I don't think advertising your guns is a very smart thing to do.
While very humorous, I agree that advertising anything, not just guns, on your home or vehicle just draws attention which may be unwanted at the least or dangerous at the worst.