What's that about watching your mouth?

Seems to be you replaced one word for another there fella, and while it's fine and dandy to disagree with my view (formed from experience of getting mixed up with a similar circumstance), you should consider keeping your forked tongue behind your teeth where it belongs and not try and be clever with supplanting words to avoid the moderators and their dislike for four letter words.
Might have been better had you more to say than 'you ******* idiot' but I guess I have the measure of you now eh?
Check out this guys reply below... it differs from mine quite significantly, but it's reasoned and objective, and polite. You could learn something from those methods of thinking and communicating.
I don't agree with this at all. One bit.
As someone who has previously been in a very abusive relationship, I can say it does make a difference if someone else calls the police.
Aside from being too scared to call the police yourself, women in dv situations are very manipulated, an normally think that this isn't domestic violence because "that's different" eg "this isn't fb... Thats women who get nearly killed but this is just a punch". It's also pretty common for women to stay because they think it's heir fault, and "if they were just better..."
For someone else to how they think it's wrong can show them actually it is.
And also the police can prosecute him even if she doesn't agree or provide a statement.
Call the police.
I guess you see things from the other side; and in the parlance of the times, acting all
big society (this is not a slur against you here) got me a load of trouble along the lines of my first post. For wanting to do the right thing caused more trouble than it was worth. Trouble with the police, social services and local residents and she went back to the man anyway. Some people just don't want to be helped, in my experience. By the time you realise this it's too late to extricate yourself from somebody else's problem and the rubbish they can heap on you.
But that's just my point of view, not an absolute or a means of refuting yours.
Op has certainly got some varying opinions now though
EDIT:
Perhaps a pertinent question should be 'How much are you willing to risk for a stranger who, quite likely, will not thank you for interfering?'
If you're ok with that so much the better, bring on the intervention, if not... it doesn't deserve the vilification evident in some posts here