It’s true that security signs can deter intrusions in Oakland
Various studies indicate that security signs are effective when looking at ways to deter an intrusion. The idea is that the burglar will see the sign and instantly determine that your home isn't worth the hassle. After all, why worry about surveillance systems and alarms when they can move onto a more vulnerable home in another neighborhood?
However, the same studies note that a visible display ranks fairly low as a deterrent to crime. A well-placed sign mostly dissuades novices, but veteran crooks will want to discover the level of security that is really defending your home prior to moving on. Other devices, like outdoor video cameras, have greater success at thwarting prospective invaders.