I was once op-uped nrt-jfk i'm not sure why, i just made plt--i "guessed" it had something to do with a complaint letter i had written (i don't remember all the details now) and i was being "rewarded". I was in the nrt AC and was called to the desk and spoke with someone on the phone and was happily surprised with my op-up.
Before i made exp, i was frequently op-uped on the redeye las-ord.
I've noticed on this route, that if there are any seats open in fc and all the seats in y are taken, probably the first person in line for standby would get an op-up.
Do they normally op up non-elite standbys to get them on a flight they aren't scheduled to be on?