Okay, let’s send the officer down to a baseball field. He can “estimate” which are the 70MPH pitches, which are 76MPH, and which are travelling at 82MPH and which are 90MPH.
He must prove his proficiency since tickets are assessed based on your rate of speed.
If he were issuing tickets to baseballs, you would have a point.
I can tell you from personal experience as a LEO that you can estimate a vehicle's speed within +/- 2 to 3 MPH after a year of traffic duty.
Yes, it can be demonstrated and stand up in court.
Ohio Supreme Court protects its own - one of the female members had multiple DUIs, tried to use her official power to intimidate the arresting officers, and STILL kept her seat on the bench.