so after a weekend away with some great friends I saw my friends young son (barely 5) in a backless booster seat. We drove together to a few places and I watched him able to move around completely and lurch forward when we stopped short. A few months ago my family was in a 4 car accident where we were at a complete stop and a lady slammed into us at 40+ mph - two cars were totaled (ours included) and two others were badly damaged. If this were to happen to them, her son would be seriously injured. There's no way the loose buckle would keep him restrained and the shoulder strap was at his neck and would likely cause more damage than help. I know she wants what's best and the booster is what her older sister used when her kids were 5 (they are 8 and 11 now) - I chose to keep my mouth shut, but will feel terrible if something happens. As I said in our accident we had been at a complete stop for at least 10 seconds - we could not avoid it and did nothing to cause it! What do I do? Shut up and pray that she isn't in any wrecks - or say something. I don't think our friendship would be damaged by a comment, but I know no ones appreciates being told they are not doing something right...if I should say something how should I approach it?