Not sure what my opinion is on Calexit, in terms of whether I support it or not. California as a unit still seems to big. I’m more excited about cities rebelling than a state. (If you look at voting maps, the US is more divided along city/rural than red state / blue state.)
If California defies the federal government over this immigration issue and the federal government retaliates by withholding funding, then California may respond with withholding its own taxes from the federal government. This is a de facto Calexit. That may trigger a violent response from the federal government. I imagine California would back down at the mere threat of violence, but hey, times are strange.
Anyway, time to start stockpiling.