Originally Posted by
UALOneKPlus
Because it can be very uncomfortable holding a lap child the entire flight, and it would be more comfortable for the child as well. If an empty seat is available, and the child doesn't disturb the aisle passenger, why not let the child use the middle seat?
If it's that uncomfortable, buy the extra seat. Don't expect the use of an empty seat because you're uncomfortable. If that's the case, then anyone who is uncomfortable on a plane should expect to use an empty seat.