I ask for the pre-board when I fly with my daughter who has severe ADHD and memory loss and needs to sit in the front few rows if possible. Never have been asked why the need to pre-board at all. I do appreciate that from the GA. She looks like any "normal" 19 y/o would, and if any passanger asked me I would say, MYOB. Call me mean.
If it matters, I go on line at -24h and get an "A", but that does not guarantee a row one or two.