We managed to stay within the 20th Century for service right until 2011, but I have now learnt my lesson and have to do on-line check even when there is no point.
The point is that other people won't have to be shuffled about to accomodate you at the last minute. For you to get your way, someone has to shift from the seats they chose in good time. So if you know you've got young kids with you on the flight, get in early please?