Hi Guys!
It happened to me not long ago, the captain just had a cigarette in cruise without asking.
I was so shocked that I immediately dropped my beer!
I asked him to open the window a bit, never saw him again
Seriously, I would ask him to tell me next time, never had problems with anyone because of that. I think the tone and the timing are important.
The "ehhh...oh yeah, let me tell you how RIGHT I am and wrong you are" or the smart ar*e way is definately wrong. Remember nobody likes to lose his face, so I guess a gentle "hey, you can fly, drink coffee, talk and smoke at once?" makes him laugh and he understands your point. If not, show him the FAT LADY!
Cheers Joe