The concepts the auto bolt go over are sound. You want to be a less desirable target than those around you. Unless you've pissed people off, the person breaking into your vehicle is after valuables. If I see two expeditions and I peek in the windows: one has some jewelry in the little coin tray, a tool box and some power tools in the back, another looks totally bare with the exception of some dirty sneakers behind the driver's door. Which one do you think i'm going to hit? Keeping you car fairly clean and empty of valuables when possible is easy and inexpensive.
Also, if you can find a way to make it harder to break in that would be good too. You said yourself you can grab a screwdriver and get into any Expy, what if you came upon a Expy and you couldn't open it with your screwdriver? Are you going to continue fiddling around with it or move on to another Expy that you can open?