America has adopted what's called the Duluth model, which recognizes, correctly, that men are the more dangerous partner in a domestic relationship with a man and a woman in it. This has... consequences, in terms of who gets arrested, and who can therefore press charges.

When a couple get into a physical altercation, it's pretty common that neither of them looks very good, behavior-wise, to an outside observer. But it has to be pretty open-and-shut assault by the woman, usually with a weapon causing serious injury, for arrest and charges to fall on her shoulders.

Although if the guy was the kind of dude where your sister thought "hey, I wonder if this guy has a record?" well, that tells its own story, doesn't it?

Pretty good argument for not publishing mugshots, though: if a woman starts throwing shit at her boyfriend, and comes at him with her fists, and he pushes her away, he's probably going to spend a night in jail if the police get called due to all the hollering. No court date or (additional) jail time, though, just gets his stuff back and goes home.