The Santa Cruz TA strike model seems to have spread beyond UC

It may be hard to remember but the strike of TA/grad students at UC-Santa Cruz was said by the union representing those students to be a "wildcat," i.e., not endorsed or administered by the union. As such, the union's position is that the strike was not a violation of the no-strike clause in its existing contract with UC. UC does not accept that position and the matter is before PERB.

That model - an unofficial strike - seems now to have spread to Columbia University:

Teaching assistants at Columbia University say they won’t teach, grade or, in some cases, pay rent until the institution offers them more financial relief in the wake of the coronavirus pandemic... Columbia has a graduate workers’ union, which is affiliated with the United Auto Workers... A majority of the bargaining committee voted 5 to 3 against striking under current conditions, meaning that this work stoppage is not an official union action...

Full story at https://www.insidehighered.com/news/2020/04/28/columbia-tas-who-say-they-cant-pay-their-rent-due-covid-19-launch-work-stoppage