Yeah, you can put this one right there along side the concealed carry badge, the shoot me first vest, and completely plastering your pick-em-up truck with gun stickers. All this home invasion sign is doing is telling people that you have guns in your home to steal. And yes, people most definitely do break into houses to steal guns so be careful who you mouth-off to about your gun collection and whom they might mouth-off to about your collection.
It doesnt take too terribly long to surveill someone to figure out when they are not home. Worse yet, if they really want it bad enough they might just be willing to shoot you to get it. Lose the mall ninja bravado. Its not keeping you any safer.