Are there major safety risks involved?

There are some things that would just piss me off. I personally don't smoke, nor do I care if someone opts to, but they can respectfully wait until the plane lands to do it. It's not the biggest deal, but I would imagine that there is some safety risk involved, not to mention any inconvenience brought to the non smoking passengers .

Personally, I have not experienced this problem, but have had to deal with a heart attack on a flight. It's not fun. For all you MD's, Medics and RN's out there, if you think CPR is hard to do on the ground (ie: moving vehicle),try doing it in bad turbulance. Then, you've seen it all.