Sign I have in the garden in back coming up the walk to the back door says simply: “WARNING! There is nothing in this house worth dying for.” There is a picture of a Glock on the bottom corner of the sign. Outfront along walk the sign simply says: “Warning - Homeowner armed and not afraid to use deadly force.”
I like it!
While I agree with your sentiment, and personally find nothing wrong with the signs, if you ever are placed into a position of shooting someone to defend yourself or a loved one, then that will all be used against you in both criminal and civil court. You may ultimately be vindicated, but those signs won’t make your life easier.