I just curious. Does it reach a point in which older kids have maxed out of boosters. Basically at what point does a booster seat no longer offer protection? I'm talking about an older child who easily passes the 5 point test. My 4 year old is in a harnessed convertible carseat. I have just recently started to let my 8 year old use a backless booster though she used a highback booster before that. She doesn't fight me on the booster seat at all but simply wants to know at what point is it safe to stop using it. I