I second this.
I see soooo much talk about theft but the stats do not backup the fear. Most reported vehicle "theft" are actually unlocked cars. The stats also have ALL car crime lumped into them, most of which is theft from the vehicle, not of - and many of them are, as mentioned, unlocked. Even stolen cars are mostly very old models without the levels of security a Cali has. Outside of that it's steal to order and full time pro crims.
People want to have peace of mind because they have a VERY expensive van on the drive, and if they need some of the toys on the van to help them sleep, fine but it is one big fear game by the companies selling this stuff.
The reality is, unless a thief breaks into your house to get the keys, that they cannot steal it without a low loader and a crane/tow. Even then they have a job on their mind to get around the immobiliser once in a lock up.
Everything else is just FUD and peace of mind.
I find not having my keys hanging up in the kitchen on a hook and a baseball bat close to hand helps me sleep the most.