I'm sorry but that is a stretch! I highly doubt you are going to have that much of a smoke stench by simply walking by someone that you will get fined.
Maybe I didn't read what you said correctly, so I apologize if I did.
No, you read it right. It's not so much the walking by, but how the smoke travels with a little bit of a breeze.
It's only stupid until it happens, though.
Side note, this did actually happen. There was a foreigner who lit up a cigarette in Adventureland THIS WEEK, and we could not get around them. Crowds were thick, and we had to follow them (Parade time crowd funneling). People around them complained, but "No English", and for whatever reason, no CM seemed to notice. We ditched them at the Penny Arcade. When we got back to our hotel about 15 minutes later, the people at the front desk commented on how we smelled like smoke, and reminded us again of the $150 for smoking in the room. I don't think there would be as much of a chance of this happening if there was just a no-smoking policy in place.