No, you have to drop it off on your way out(dont' have to stop at the window or anything, just take your name tag off and drop it off)..... I would definitely get a double(or two singles). Your 6 year old may not want in it all the time but will DEFINITELy use it some. Yes, it is doable for a 6 year old to go without, but since the 4 year old will be in there, he will want to sit sometimes. It is a great safety trick too... they are a bit confined, keeps it easier to keep track of them. Well worth the cost, in my opinion!!