Now, of course, I would say this... But, I am of of the nicest, most caring, friendly, helpful, polite and respectful people you would ever want to have looking after you onboard an aircraft... But... In the right (or read possibly wrong...) situation, you would not want to cross me.
Of course, different people need to be approached differently and this also applies to this situation. For example, if someone has a mental health problem or learning difficulties, this needs to be approached in a different way than someone who is doing it because they are intoxicated.
I will never forget during my initial training some years ago, during our Aviation Security and Hijack training, the inference as to what would be expected of us in protecting the flight deck from an attempted breach, and the lengths we would be expected to go to and how to use different items that were available to us within the cabin environment to accomplish this.
I do consider myself to be rather good at cuffing, and do look forward to that part of the recurrent training every year... I am not sure what the reason for that is though...