We have recently moved closer my mil, she's normally lovely and we get along great, I am respectful and polite with her. She has a large house with a games room with all the board games, kids toys dvds and TV. This is usually where our kids hang out. When her daughter comes to stay she smokers in this room. I don't want my kids to play in this room when she's been smoking there all day, even after a half an hour airing because I still think it's smoky and harmful for them. The house is big, there is plenty of places to play. Mil thinks I'm being silly. Aibu?