Zacs - Simply saying 'Children hear it anyway ...' is not, in my view, an approach that helps.
I taught my children that language and behaviour varies with circumstances, and part of growing up is learning the appropriate settings for different language and behaviour.
I would point out that working with telephone engineers, I have already forgotten more swear words than they will know, but they will never hear those words come out of my mouth when speaking to them, or their mum, or any family or friends, and I don't expect to hear it from them either.
It's about time and place, and people being aware of what is and what is not acceptable in present company.
So I never thought 'They'll hear it at school anyway...' which of course they did. I tried to point out the sense of surrounding that makes language appropriate, or not, and to use it accordingly.