Why have the supervisors been muzzled?

To deal with the Mirkarimi fiasco, the Board of Supervisors has been provided a lawyer from outside city government, Scott Emblidge from the firm of Moscone Emblidge Sater Otis, to avoid a conflict of interest by the City Attorney's office, which of course is representing the mayor.

Apparently Emblidge has told the supervisors that they can't say anything about the Mirkarimi case before they vote on removing him from office. (Supervisor Olague: "We can’t talk about it, because we’ve been prohibited, because we may need to weigh in on it at the Board level. So we’re not allowed to comment on that at all...") 

The supervisors have complied, though it's not clear that they should. Is there anything in the City Charter---or any other law---that requires them to be mute on this important issue? Or, like most lawyers, is Emblidge simply advising them to shut up so that they don't say something that would complicate his job?

Could a supervisor, like a misbehaving juror, be disqualified from voting on the issue if he/she spoke publicly on Mirkarimi's behalf? Lawyers often advise clients in non-political cases to not say anything that might hurt them in court. 

But supervisors are political representatives on the most important policy-making body in the city, not ordinary clients, and the mayor's attempt to destroy Mirkarimi is more of a political process than a legal process, as Larry Bush has pointed out nicely once again.

I sent this message to Emblidge asking about his advice to the board:

Mr. Emblidge:

I'm told that you have been retained to provide our Board of Supervisors with legal advice on the Mirkarimi case. Supervisors are saying that they have been advised by counsel to not comment on the Mirkarimi case before they vote on removing him from office. Is there something in the City Charter---or any other law---that requires that the supervisors refrain from discussing this important issue in public before they vote?

The response: "Thanks for contacting us. We will respond to your request as soon as possible."

Later: There was never any response. Of course it was all bullshit, and Supervisor Olague and other supervisors used it as an excuse to not comment on a thorny issue.