I don't have 'rules' about smoking per se, as I've never had to. But watch out anyone who starts smoking around my boy - it's probably the thing I feel most strongly about! I will time my entrance to shopping centres if there's people smoking outside - we will pretty much run in the door!
I too am 'allergic' to cigarette smoke. Fortunately no family or friends smoke so it's not an issue we've had to deal with.
I've had to move house when I was at uni because the neighbours smoked and have had to change hotel rooms a few times because of the smell of stale smoke. I just have to scoff when I hear people say they don't smoke around their kids/their partner doesn't smoke around their kids (and so what they're doing is perfectly ok) but they still smoke in the house where their kids live, the car where their kids sit etc. The carcinogens don't just disappear when the smoke goes out! It would be a deal breaker in any relationship (including friends or a partner whose close extended family smoked).
I taught a child once whose family were obviously heavy smokers - he absolutely stunk of smoke. His homework book would stink so badly I'd have a coughing fit every time I went near it so I started getting the children to correct their own homework and glue in my comments so I didn't have to touch it!
Rant over, point made!