My opinion. You were very brave. Anybody at anytime .. could do could do something on your aircraft. A passenger could get on board completely sober., and then go wild with the walking Johnny in J class and decide to dance naked in the isle. But you cant stop him from him (or her ) from boarding in the first place.
And if you have done this in the ME ( where the customer is ALWAYS RIGHT) and this person is a celebrity with followers
I fear your meeting might have no tea or biscuts.