One thing that would have me worried was if the PIC chose not to divert after the bottom pinching episode and later in the flight the same pax did something more inappropriate causing actual injury to crew or another passenger.
You can just imagine the passengers (crews) barrister to the PIC on the witness stand..
Q. Did you have any idea that the passenger was unruly or prone to bad behaviour ?
A. Yes, But I thought it was going to be OK
Q. Well, since the passenger subsequently did *insert bad things here * obviously your judgement was wrong ?
What's your next response ?
A1. No my judgement was correct
Q1a. Well obviously it wasn't, the passenger had previously assaulted a crew member on your flight in front of 200 witnesses and he did it again.
Q1b. What qualifications did you have to be able to judge his mental state, are you a registered psychiatrist ?
Q1c. Does your company prohibit you from diverting if a passenger assaults a member of the crew or a fellow passenger ?
OR
A2. Yes, My judgement was incorrect, and as a result of that *insert bad thing* happened
Ever been on the receiving end of a tongue-lashing from a switched on barrister ?
Let me tell you, there's no right answers to the questions they ask !
CYA !
S_T
How about the beak that allows a drunk driver off with a warning and subsequently drives drunk again and this time kills some one?
How about a person who is a little rude whilst boarding, we all hear them, mabe running late or something similar, should we throw them off just in case they get more aggressive later in the flight and it becomes an issue where someone gets hurt?
You make a sensible decision you can justify based on the current and likely circumstances. That's he best we can do, leave the lawyers to fight the rest out at a later date.