We have a 2011 Sienna. We've had to put the 8th seat in since we've been carting an extra kid or 2 around a couple times a week. In this situation, we put my daugter in the 8th seat as she's the smallest of the rest (all other children in the van are 5' tall/11+yrs and in regular seats). She was in a NBB in a captain's chair since this summer until we had this arrangement and she outgrew her regent. Her booster doesn't fit in the 8th seat. She does 5 step in it though. Would you allow her to stay in the 8th seat even when there are empty seats or require her to move to another seat and use the booster when you are without extra kids. I've been hesitant to do this because of having a loose booster seat hanging out in the van when it's not being used. She has a graco turbobooster nbb. Just wondering what you all would do in this situation.