Lol thank you for asking. I get to tell my favorite non-rev story.
In the summer of 2005 my wife and I and our three kids, aged 9, 8 and 4 were traveling back to the USA on Northwest Nonrev passes. At the time those passes were only good on NW. KLM had a different pass, I think they were ID 90s or something. Anyway, they were trying to get from AMS-SFO. I was going to SEA. I tried to see them off at several gates on NW flight through Detroit and Mini, all full. The KLM agent asked us why we didn't try to take the KLM nonstop 747? I showed her the passes and said, "that's why." She was undetered. "Follow me" she said. So we did.
Even though the 747 was full she worked the computer trying to find us seats. It was after departure time and security (done at the gate) was gone. She said she was sorry but the plane was full. Just then the captain came out the jetway door and walked over to us. "Are you the Alaska guy trying to get to SFO?" I said I was, or at least my family was. He looked us over and asked if my kids could keep quiet. "Of course!" I said. He took them down the jetway as I waived goodbye. All the CSA could do is mutter, "This is highly irregular!" I waited until the jet pushed and found my plane home to SEA.
When I got home I couldn't wait to find out what happened. Turns out there were still 4 seats available. The captain sat my wife and daughter in the center galley jumpseats and took my 9 and 4 year old sons up to the flight deck. After a short tour he put them in the sleep closet behind the flight deck until after takeoff. They spent the rest of the flight in the center galley with the wife and daughter. Pretty freaking cool captain.
The moral of the story, anything can happen. KLM captains have a little more authority than we do. I shouldn't have been surprised. I flew some KLM flights as a contract captain 14 years earlier. I was treated like gold when working KLM flights.
I might suggest you bring along a small box of fine chocolate or something like that and give it to the cabin purser. She will like that and you might find yourself upgraded just prior to or just after take off.
Good luck.