I have a 5yr old daughter who sits in the backseat on a booster. The booster meets all safety standards, and is one without a back or head support. The typical booster seat that many parents have for this height and weight of their child. If you look at the diagram, there is no locking position at the normal position of the headrest. Many other manufactures like Subaru, Porsche, etc have a locking position in the normal position for the headrest. Just with normal sitting and being a kid, the headrest pops up into the first locking position. Happens every day. This causes the back of her head to rest in a "pocket" between the top of the seat and the bottom of the headrest. I believe in the event of an accident where force comes up and outwards (like a bad rear collision), friction would cause her head to want to stay in this pocket causing her neck great pain and even damaging her neck.

- Greensboro, NC, USA