Urm....maybe you should just go and smoke outside then, and you wouldnt have this problem.
Im sure if you owned a house/apartment...and you were renting it out to someone, and you had it noted you didnt want them smoking in the house, youd be pretty quick to claim money from that person for any potential damage that may have come to your property if you found they were smoking inside it too.
I wouldn't say that letting agents or landlords are out for anything quid they can get. If you weren't smoking inside, you wouldn't have the concern that they would try and claim against you for such things....so....just outside and bloody smoke! Problem avoiding completely!