Maybe you haven't been around as many cops as I have, hearing stories about whistling into/around some older models can increase the speed it displays. Cops giving citations when not at rest, and driving, or around a lot of curves.

A bit of anecdotal evidence, a while back a friend of mine at the time, had a ford escort, think it was an 88 hatchback. The car could barely do 70 on the highway, and dip down to 60 on inclines, and could only go above 70 going down hill. We were going up hill, it couldn't have been any more than 35/40 in a 45. The officer said he was doing 90. So yeah, in that case, I know for sure, either the officer was lying, or if their gun actually said that, it was not calibrated correctly, or they didn't have the training to use it properly.

I am personally a fan of speed, but if that car was capable of 90mph up a hill, would you want to be in it? Well if you have ever been in an older Ford Escort, that wasn't all that well maintained, I am sure your answer would be hell no.

I have seen tickets where it was clearly marked at such and such speed, and the cop wrote over it, at a lower speed to increase the penalties. Not all cops are like this, or bad, but not all are angels either.

Now with all of that said, could the person be full of shit? Sure, but they could also have been in a situation like that before, and knew they were not speeding and got ticketed.

The only speeding ticket I ever got, was from a cop coming from the opposite direction, the car in front of me was pulling away from me, and I was doing probably 43 or so in a 45. I seen the cop car, looked down at the speedometer, and it was a line or two under 45. I got a ticket for 61 in a 45. The car in front of me, started to pull over, but when they saw I was being pulled over, they went on. I can't remember what it was plead down to, but I think they said they could only go like 8 mph lower, so I believe the ticket was for something like 53 in a 45. I would have fought it, but didn't have the time or money to really do so. But if it happens again, I will be asking for the dash cam footage, and the maintenance logs, last calibration, etc, as well as taking photos of the scene, and detailing the situation the best I can.