I'm on the fence with this whole thing.
I often tell other peoples kids at the park to mind their language when mine are about. I don't think it's right that 10 year olds are f'ing and blinding to their hearts content. If they were being supervised I'm sure they'd hold their tongues... but that's another issue.
I reported a user on a game that my kids play, the username repeated the c-bomb twice. It's a PEGI rated 3 game, so didn't expect to see that.
Now my kids (5 and 8) know some swear words, but they know that swearing in the house or at school is going to land them in trouble, so I encourage them not to. They know they're just words, but when they're in a world with no filter, be it other people in public, seeing it in supposedly safe games, or even out and about on graffiti or tshirts, I feel like I'm fighting a losing battle. They are just words, they'll know them and use them eventually, maybe it's not as big a deal as I think it is.
There will be a time when I have to explain what a 'cee you next tuesday' is but I'd rather not have to do that with a 5 year old.