For sure, and a proper fitting booster seat or car seat goes a long way towards a child's comfort. At three in a car seat, it means either the boy is small for his age (still under 18kg) or he's squeezing in and the straps bind. I don't have kids myself, but I come from a big family. Having been in an accident (passenger, rear-ended, in the UK) with a child not in a carseat and I'd repeatedly told his mother about the dangers, but bit my tongue for family sake, it just makes me want to smack parents and make them realize how fragile and precious a gift they have. If that means when you can't afford to buy a new booster seat that your son is uncomfortable a bit, isn't that worth his life?It only takes one time.
I'll listen to anyone's point of view on any topic, but there are a rare few that I have an emotional attachment with that won't sway. This is one of them. I'm sorry if I come off too strong, but IMHO a good parent looks after their child to the best of their ability.