Our elder DD has just turned 7 but is both small & slight for her age. She is in a Britax Evolva car seat (using the car's seat belt rather than the 5-point harness). A lot of her friends are now using basic booster cushions with no side impact or head/ neck protection. Does anyone know of any good websites or videos that we can show her of crash tests comparing the two? I think a piece of film might make her realise we are not just being "mean making her use a baby -ish seat".
(Tis also challenging trying to explain it to her without slagging off other parents as a) not a good general policy & b) likely to get parroted back to people. 