Many people have & use such signs for dogs & cats, but for herps it will probably help you get burglarized...
The only way I'd do that is on an INSIDE door into snake-room...but that would never work for me, my snakes are always throughout
my residence, even when I kept rattlebrats.
I think Zelda would be a good deterrent there. Also the PD is 2 blocks away and the entire community keep an eye out. I am lucky there.