I have 2 stickers on my car. One is a zombie hunting permit and the other is the arrow in triangle russian arsenal mark. The zombie one is possibly the worst since it might make people assume firearm but its not overt... and the symbol... nobody but those familiar with factory markings would understand it.
COurse my car is pretty shitty looking and the house is modest... but I should probably sell off my padded rifle cases for more discreet alternatives.
also if i were the criminal type.. i wouldnt follow the cars home... I'd jot down the plate numbers and do searches online and go from there.