what happens if the seller doesnt put anything in the listing to state pet/smoke free or not pet/smoke free

what if your place is smoke free but a buyer says item stinks of smoke

what if  its a  brand new item  with or without tags brought online and resold a week or so later

how would we respond to this.if seller didnt smell anything on it

also what if seller uses only citrus sprays in house and an item smell of this

just curious these are a few ive seen online strange ones

also one was about candle smells

these question can refer to any type of item

tara