I used to work for BCAL years ago, and am still involved in travel though, sadly, no longer able to get concessions.
However, whenever I did fly on staff tickets, we were under the strictest orders to be on first class behaviour at all times, not just on the aircraft but on the ground too. We also had to dress immaculately, no jeans, trainers, etc, etc.
A couple of years ago I was on a full flight to MIA. There were a number of staff passengers boarded at the very end. I was in Premium Economy - seat 17A - nice bulkhead with space on 747. I'd booked online the day before to get just that seat! A few minutes after boarding a lady (?) approached in jeans and trainers and asked if I would move to a seat at the back of the cabin. I politely refused saying I'd really wanted to sit there. Her response - "I wouldn't want to sit next to a bitch like you anyway". Nice! Stupid woman though - she made her comment right in front of crew member who immediately reported it to CSD. I later saw him talking to her in no uncertain terms.
Had I done that as a staff member years ago, I would probably have never got a staff travel ticket again.