How far is too far before producers would kick off a cast member?

IMO Brook and Gia's behavior was above and beyond what's acceptable behavior. It borders verbal violence. At what point would producers kick off a cast member for bad behavior, or are ratings the ultimate goal for them no matter what? Has a cast member ever been kicked off in the history of MAFS?

I remember back in the day shows like MTV's The Real World, if a cast member was violent in any way, they were kicked off.