Hi ooh-la-la (I love your username) If you said no smoking then this means no smoking, come on just how lazy are people that they can't get to the front or back door for a ciggie?
She maybe smoking out of the window hoping that there wouldn't be any fumes in the room but this is entirely dependant on which way the house is faceing and wind is blowing but this is still irrelevant as this is still technically smoking in the room.
How good is she in other fields, clean, quiet, friendly?
If she's good in other fields then have a word with her that you hate and are sensitive to smoke and you can smell it coming from her room, if she carries on then tell honey to buy a crash helmut because that kerb she can see outside from her window, yeah she'll be hotting it soon.
Good luck hun. X.