At least, that's what Luke Thomas is reporting in Fog City Journal . He's got photos, too.
The way the story goes, Bates was speaking at a PG&E-sponored forum, and Mark Toney, director of The Utility Refrom Network (TURN) came up uninvited to speak out against Prop. 16.  So the mayor of Berkeley physically pushed him out of the way.
Now, why Tom Bates was speaking at a PG&E-sponored forum (and saying nice things about the company) at a time like this is beyond me. And typically mayors don't take it upon themselves to eject protesters from meetings.
I've got a call into Bates for comment, but his staff hasn't gotten back to me.