content: Even those are vulnerable. My dad lives in an area with some crime popping up recently and people have broken into cars with universal key fobs. They drive slowly unlocking all the cars along the road and then come back later to get them.  I've witnessed both cars parked in the driveway get unlocked when we are pretty religious about locking or cars when we go inside. I am not sure how it works exactly but I'd have to imagine it's similar to those TV be gone remotes where it just cycles codes in a sort of brute force attack.  I removed keyless entry from my car so it won't ever happen to me