Diversion is expensive to UA. I would give UA/FA some credit for knowing what to do. My first experience with an unruly passenger was 2 days ago with over 2 m miles of flying. Personal, I was scared of being trapped in a metal tube with that passenger. The crew handled it perfectly. We completed the flight without an incident. I am very impressed by the UA crews.
It was an United express flight. So technically it was Mesa air crew.