She's going on a nursery trip on the bus. Thing is, she's still tiny and only 13.5kg at best. They have booster seats, and high back booster seats for them but she's technically not heavy enough for them (15kg). They might have group 1 seats with 5 point belts, but I don't know how well these would fit the narrow bus seats (buckle crunch etc).
AIBU being a bit jumpy about this? I've offered to drive her but she wants to go on the bus with her friends, and the staff think it would be a shame for her to miss out on the bus bit.