B.R.
I agree that it is a discipline issue and that you can't be sure of any device intended to keep a 'houdini' child in or out of anything. It may not be as easy with your son as some are suggesting... though I hope for your sake and his that it is. But, just stay firm with whatever form of discipline you choose to use. Remember not to panic if you see him out of the seat while you are driving. Calmly look for the safest place to pull over and then deal with it. Remember, for many, many years seat belts and child safety seats weren't required in cars... in fact I can remember when they weren't even available for cars... and children and adults alike survived. Not that I'm saying the protection isn't a good thing in the case of an accident, but it's better for you to stay calm enough to avoid an accident rather than get too excited over your child having escaped his carseat. If you happen to be pulled over by an officer who sees him out of the seat, you can explain your situation... and depending on the officer, they might even be able to put some respect for the carseat into your child.