If it were protection .. to prevent a lawyer from witnessing something at a public venue that might be used as evidence agains them ... then there is no protection possible.
A sensible law firm would not use one of their employees with a public image available, they'd use a contracted private investigator to gather evidence.
This smacks of punitive behaviour to not only punish the law firm (for doing their job) in a petty manner, but to also intimidate any other law firm thinking of taking them on.
Eg: Hypothetically if Disney were to ban all members of any company that challenged Disney on ride safety .. how would that appear?
Or just, like, not doing this at all. This is James Dolan, the owner of Madison Square Garden, being petty as usual and banning people from the venue who annoy him. e.g. Spike Lee for saying bad things about him, Woody Allen for the wrong reasons (he refused film ads for Dolan), &c
I am under no obligation to contort myself to assume good faith on his part in the face of a pattern of behavior that indicates otherwise.