If a speed trap defense would work, and I don't know whether it would, then yes, it would be worth doing in my view, depending on how much it costs the individual to attend court again. If you're pointing out that the judges's screw-up (and assuming what OP says in true, the judge did screw-up) then maybe you're agreeing that the Appellate Division should dismiss in the interest of justice. I mean, if the Court Clerk was to assign a different court date by mistake to a defendant and they were convicted because they didn't show up, would you want them to come back again? Maybe we could make a new rule for California Courts where the defendant just needs to come back to court when the officer doesn't show up?