Equity warns its members not to work with Tucson’s Chamber Music Plus Southwest. But “we’re not a theater organization. It doesn’t fit. If we were a theater organization, where actors came in for a week at a time and you had costumes and sets, that’s Equity. What we do is no different than what the New York Philharmonic does. . . . It’s a guest appearance by an actor; it’s not an Equity situation. But they don’t seem to understand this.”