Thank-you both.
The truth is she doesn't need one at home either! She is tall for her age and the seat belt fits fine and we had allowed her to give up the seat about a month before the new law. She is no safer in the little booster than in the seat belt but the law says she must so we do it. Maybe less so because the booster isn't bolted down like the big seats are. Sorry - It is just another law that isn't needed for this age child. Trust me when she was little I would NEVER consider her being out of a real car seat. I have taken it on the plane MANY times!