Never give a policeman access to your phone. There just isn't any good reason to do so. Ever. Nothing they threaten you with is worse than what will happen if they get access. Even if the data on your phone clearly exonerates you, you will be prosecuted for something else. Better to have them fixated on what they can't have than what they do have.
Based on past experience with California propositions: this one will fail. The problem is this.
1)most people vote NO on propositions as default.
2)most people vote NO on propositions they don't understand. This one's benefits are not obvious and it seems confusing to the average illegal .. I mean Hispanic voter.