There is a thread on one of the VW forums where a very similar question was asked. In this case, the scan device didn't record the actual speed, but it can be calculated based on RPMs. Depending on the state, sometimes defending yourself and presenting evidence, if done correctly, will get you out of a ticket. I know because I've done it in Maryland. However, from my experience, the best thing to do is go to court and hope the cop doesn't show. If he does, like WormGod said, plead guilty with an explanation. Tell them about how you have a bladder control problem and really had to do #1 so you were rushing to make it home. Or whatever. It really doesn't matter what the excuse is because as long as you are courteous and respectful, dress appropriately, and present yourself in a positive manner (and don't have warrants or a record a mile long, of course) you will almost always get your fine and points reduced.
If you are positive that you weren't going 94 or darn close to it, and that the cop's estimate was way off, you might have a chance at going to trial. But if your scan device doesn't save the trip log with time stamps and everything, I think you'll have a tough time getting your evidence accepted and at that point if you're found guilty you'll pay the full fine and get all the points. I've heard of people asking for laser calibration records and such, but I don't personally know of anyone who has actually used that tactic.
Regardless of the outcome in court, unless the charges are dropped, your insurance record will reflect the new ticket and your rates could go up (it all depends on the insurance company).
There is a lot of interesting advice in that thread. I'm not sure if you'll need to register to read it: VW thread
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