My 3.5 year old son, 35 pounds, 40 inches, rides RF in a Sunshine Kids Radian 80. Due to new LATCH limits we have it with a seatbelt install. (The seat weighs about 26 pounds.) When I arrived at karate class yesterday, he had unbuckled the seat from the car (not his harness, but the car seat belt holding the seat in) and pulled the belt out of the belt path and was playing with the belt, all using his feet. I think the lecture I gave was scary enough to keep this from ever happening again, but does anyone have any other suggestions o make it less possible? I wanted to keep him RF until 4, but I'd turn him if that would make a difference... I think he'd be able to do it with his hands then... Ideas?