This seems equitable.
Did plaintiffs engage in sanctionable conduct? Yes. Definitely. So sanctions are proper.
Who was responsible? Primarily, the attorney, Howard Shanker. He was representing the clients -- who filed an environmental lawsuit to stop a ski resort -- pro bono. Are the clients legally responsible for their attorney's conduct? Sure. So we could sanction them.
But the Ninth Circuit doesn't. It holds that the clients were misled by their lawyer. And I can definitely see how that might well happen. You're putting your name on a caption alongside many other people in order to create standing, and have little (if anything) to gain personally from the lawsuit. What you know about the lawsuit comes almost exclusively from your lawyer, who's not billing you (so you have very little reason to actively supervise him). It's very plausible that if your attorney deceived you or engaged in sanctionable conduct, you'd never know about it.
So I like what the Ninth Circuit does here. Sanction the lawyer. Leave the individual clients alone.