Read The Proposition.

The 6 Californias part is really just advisory. No proposition can force the issue. Legislatures (State & Federal) must be involved.

However, there's another kicker in it: if it passes, the state must pay local governments whatever the locals think it might cost to obey state laws. Object is to prevent the state from doing anything that might affect how local government operates, for good or ill. So whether or not 6 Californias ever happens (unlikely), if it passes Sacramento will essentially become a debating society with no ability to actually enforce laws related to local government operation. I'm sure that's unconstitutional, but for a while at least (while the courts work it out) we would be in essentially anarchy.

Have fun with that one! I strongly doubt that anybody signing the petition saw that.