I'm prolly a "non-standard" player in this regard.
I try to "check-6" everyone I see in danger of being flamed, mindset being: not everyone, especially new players has a good situational awareness and some folks can use all the help they can get so I err on the side of caution instead of letting everyone fend for themselves. I also do my best to clear every six I see in danger as best I can, being far from being a good stick myself.
Normally--I hollar out on VOX--"Hey [ID] ya need a hand over there?" If there's no reply and they look like they are on the short end of the fight I ask again. I try to be non-intrusive if the other greenie thinks they may have a shot of turning the fight around and flaming the red guy.
If they reply they need no help I leave that fight alone and it would be nice if others did as well.
For the most part it seems MA/LW is pretty much a free-for-all for furballs. I do not normally furball but most folks just seem to be out for themselves.