Originally Posted by Grumpy
As the saying goes "A lock just keeps a honest person honest".
While this is true, there is still something to be said for changing the locks. If someone comes along and wants to get in an RV, but they don't have the key to yours, they will move on to an easier target. It won't stop someone determined to get into your RV, but it makes it less likely for your rig to become a random target.
Same thinking applies to home alarm systems. Really, you don't even need the alarm system. Just the sticker in the window or sign out front. It's easier to walk to the next house down the street without an alarm than to deal with the alarm in yours.