Joey Barton Arrested Again

When will Barton ever learn? This time it looks like he's had a bust up with a taxi driver and is facing assault charges. I'm wondering when the FA will step in and take action over all this. Surely at some point they have rules over player conduct that will allow them to say enough is enough. Or will they just sit back and watch Barton self destruct? After all, if Stuart "Psycho" Pearce can't tame him who can?