If you think about it, not many of us are not familiar with the smell of smoke. I think it would be pretty rare in most places for an animal to have never smelled it before. A lot of people say it's just another smell that will spook the animals... I don't take that view - with one exception! If you've been busted because you are stupid and you smell like smoke, they will begin to associate you with that smell and it will backfire... just like any other smell out there.
Take this all with a grain of salt and remember what Small's kept telling himself in the movie Sandlot... "Don't be a doofus, don't be a doofus!"