V.W.
Yep.. .it's a stage they seem to all go through. I remember wishing they sold a device to stop that sort of thing... like child proof covers for door knobs, lol.
It was many years ago for us. Our son had undone the seat belt that held the car seat itself into the car! Only we didn't realize it. We were on a road trip, and were stopped by a state trooper doing a routine license check and he asked me to step out of the car. I had no idea what was going on... He said "were you aware that your child isn't buckled in?" Of course, I thought he WAS and he WAS (to the car seat)... but the car seat itself was not secured to the CAR. I was shaken up by that. I made it a habit to always check that and talked to my son about it too. Being able to tell him that the police were checking that sort of thing too helped, I think. lol