That's a hard one. The very act of taking control from someone who doesn't want to give it up could be the cause of an incident.
I'd do it if I thought I was going to get hurt and doing so wasn't itself going to get me hurt. Then at least I'd be alive to suffer the fallout.
Other than in a formal environment, FI/student or multi crew, what right does any of us have to do such a thing?
To answer your second question... if I were on the receiving end of this behaviour, it would depend who it was. If it was an FI I'd flown with in the past in a training relationship, I'd probably accept it as necessary. Anone else, unless I could agree with their reasoning, I'd report them and have them prosecuted for unlawful interference or whatever was possible, I suppose.