I did not have to deal with my wife's behavior onboard when I had staff travel privileges as we were separated at the time and she was not informed of said privileges.
The young children were on their best behavior onboard.
For older relatives, perhaps HR departments should have them sign that they have read the rules and that their travel privileges depend on their following the rules.
I was always polite to all staff and invariably found myself and my children welcome.
An AC gate agent deserves a special note of thanks for upgrading some full-fare Ys to accommodate three interliners who got bumped from their own outfit