I've smoked. Most of the people around you smoke as well. The most that'll happen if you get caught is, "Hey, can I get a hit of that?" haha. :D
My rules tend to be "If I can't tell it's going on, neither can anyone else, but if you put me in the position of another RA walking down the hall and seeing you all breaking the rules then that makes me look bad."
There are SO many other places to smoke, to put the entire dorm at risk of having to evacuate due to the fire alarm going off is just inconsiderate in my eyes.
Or at least it is where I go. I'm not gonna be ignorant and generalize every single dorm there is, I don't know how others work or are regulated and kept patrolled or something like that. But I sure can without a care here! =)