6yo is doing amazing in a booster and stayed in position when she fell asleep, but she's only done short drives and we have a road trip coming up. I'm tempted to put her back in the harness because I'm worried if she sleeps soundly she won't stay in position. WWYD? How did you decide when you could get rid of the harness for good? Thanks! I guess I'm having trouble with this because I planned to harness to 7, but she's really surprised me and she's feeling such pride in this accomplishment, I don't want to undermine that.