Al sent this.  Take a look.

So.  Here we have a thinking, ambulatory sidewalk that blocks the fire exit occasionally, at which time smokers are advised not to stand on it.  Alternatively, we have the suggestion that smokers might be likely to idly hang about on the sidewalk in the case of a fire.

“Hey, look, the building’s on fire!  And I think there are people trying to get out of that door behind you, dude.”

“Eh.  I really need a cigarette.  Got a light?”