They are both SAG-Aftra members, but they are doubling down in the face of criticism from educators.
Maggie Gyllenhaal and Viola Davis appear in the film and broadly support its message. Gyllenhaal stipulates that she's pro-union, but all is not well with the teachers unions. Davis said of the protesters, "There was not one person -- I guarantee you -- that was outside there protesting with a picket sign who had their child in a failing school."
http://articles.philly.com/2012-09-28/news/34149452_1_anti-union-bias-teachers-union-top-charter-school
"There's no world in which I would ever, EVER make an anti-union movie," she {Gyllanhall} said by phone. "My parents are left of Trotsky. That's just not my world, and neither is it Daniel's {Gladwyne-raised director Daniel Barnz}. I don't know Viola's politics actually, so I can't speak to that. But I think that's just such an oversimplified way of looking at the movie - that it's anti-union.
"But clearly - and I don't know anyone who'd disagree - there are huge problems with the teachers union. So you can be in support of a teachers union and unions in general, but if you don't take the time to look at things that are broken - even inside something you support - then it will fall apart completely. Can we not even take a look at ways that the teachers union isn't functioning without being called anti-union? That would be so destructive to creating continually functioning unions."