Delta/UG
A couple of weeks or so I was upgraded gratuitously on 2 segments; I just assumed that was the way it is.
On a flight overnight from LAS to YYZ on July 13, I had a discussion with the gate agent who nicely but firmly declined and said I was not eligible and the computer would not accept it. I then asked her to check because I was then under a misapprehension of entitlement. She checked everywhere and got a Supervisor involved. Accepted her decision to not recognize AS MVPG.
Was in the process of boarding (had a very good exit row seat) when I was paged.
Same agent said that because I had said "it was not the end of the world, and no big deal - don't worry about", that she extended the upgrade and thanked me very much for "flying with us."
End of strory.