It's a bit pricey but graco nautilus 5 point harness goes up to 65lbs and comes with the booster to 100 lbs. I don't think a child would need up to 100lbs but I don't know. 5 point harness is SO much safer. There are people that have rolled their cars with the nautilus 5 point harness and their child was unscathed. I know they are pricey (5 points in general) but if you can swing it you should. Your fiance's daughter is worth it (I hope so) :D
They aren't death traps lmao. The 5 point harness is just safer, wasn't that your question?
Booster seats sole purpose is to raise the child up so she can fit in the seat belt like an adult. The 5 point harness holds them snug so if the car were to wreck you have either a seat belt or a 5 point harness keeping you safe. I'd rather a 5 point harness. That's why race car drivers wear them and the loop around roller coasters. They are safer.
I'm guessing your fiance's daughter has a car seat, can't you buy one for the other car? You are speculating buying a booster, why not spend a bit more and get another car seat?
Thank you Rachel K, I couldn't agree more. I love knowing my daughter is safe, even if it's a pain moving it from my car to my dad's truck that has those 1 1/2 doors, such a tricky maneuver. But I love knowing my child is going to be safe if something should happen.