I have wondered about that skimmer issue as well, not just with smoking ( I recently quit and am on the patch myself), but I have my cat's litter boxes in the fish room and they are loaded with amonia...I know it can't be good, but the tank is doing well. Maybe all the extra amonia beefs up the biological filter...or maybe i am just reaching now. My skimmer does have cotton that goes in the air intake and it does turn black and needs to be replaced frequently. That should help filter out the smoke contaminants from the skimmer injector.
Lisa
PS. I have read about tank crashed that were credited to smoking, but it was a lot of smokers in a small area. Like having a big party in an apartment. You never know what else the drunks put in the tank though. I would also worry about this scenario in a bar.