Originally Posted by MacCool

I agree, but that's not what he said.

But you're right. If you go to court having plead not guilty, your attorney (or you if you are acting as attorney pro se) on cross examination will ask the cop to prove that you were flashing to circumvent the law. He won't be able to. You'll ask him, "officer, is it possible that I was flashing because I missed the turn signal, etc etc etc" and he'll say yes. But let's look at the practicalities. When it's time for the defense, (you), to present your case...what are you going to do? Call yourself as a witness? No, you wouldn't want to do that because your choices then are going to be either lying under oath or keeping silent. You can keep silent, but in traffic court (rather informal), I'm pretty sure the judge is going to ask you why you flashed your lights. Your choices now are lying under oath, or pleading the fifth amendment. Not good. If you do that, I suspect that most judges are going to find for the prosecution and tell you they recommend you appeal if you disagree.

Smart move, if you decide to take such a case to court, would be to move for dismissal before presenting your case, asserting that the prosecution didn't prove its case. I'll bet the odds are no better than 50-50 that the judge would go for that.