We are flying next week and our 23 month old is ticketed as a lap child. I was just looking at the seating chart for our flights and see that both planes are currently about 1/3 empty. I know that can change between now and next week, but if we carry on a car seat, will the airline let you use an empty seat for someone who is supposed to be a "lap child"? We're flying United if that matters - certainly don't want to do anything to get on their bad side these days