The Vehicle Code requires the prosecutor to establish that the driver was using the device while driving; it is not enough that the device was on when the driver was pulled over. To collect the necessary proof, some law enforcement agencies are getting creative:
Whether it's a speeding ticket in Kern County or a mass murder prosecution, the state must prove every element of the case beyond a reasonable doubt. California defines this term as "proof that leaves [a juror] with an abiding conviction that the charge is true." In other words, the evidence against the defendant must be so overwhelming that even after telling his or her side of the story, the juror still believes the prosecutor.
Reasonable doubt is a very high standard, and an attorney practicing in Mojave can concede to the jury that there is evidence against the defendant, but not enough evidence to warrant a conviction. Some high-profile trials in the last twenty years, such as O.J. Simpson and Casey Anthony, are excellent examples of this point.