Yes, with the assistance of California's AG and tested at the appellate court level. A validated gangster can't loiter in well defined areas at specified times.
Association is already covered by parole but simple public appearance is a quicker picker upper and preferred by law enforcement because no time consuming surveillance or consequent, judicial appearance is required of a sworn officer.
Now I see you. Now you're in jail for the night (just like a drunk). Plus, there is always the possibility of a bonus, free trip back to state prison, should the gangster be caught holding or in the company of other felons.
Cool, I can live with that.