We will be carpooling to an after school,activity once a week this school year. DD1 is barely 35 lbs and is still harnessed in our primary cars but does ride occasionally for short distances in my parents' car in an Evenflo Amp HBB. The Amp is rated for 30+ lb but I did not realize not not all HBBs start at 30 lb. The other family we will be carpooling with has a few extra HBBs since their DD is now in a LBB so they said I don't need to provide a seat. Now I'm wondering if I should provide a HBB for them to use after all or ask to see their seats, since I don't know the minimum weight of their seats. Thoughts?