Don't take it personally, Jonesy. I'm not really picking on YOU, I'm merely pointing out that guesses are as good as a mile. Let's not forget what weather was initially predicted for D-Day......... that didn't work out so well, either.
Back to the original topic, I would go to court on any speeding ticket issued by a guess. I still say that without PROOF, an officer's estimate, no matter how good they think they might be, should NOT be used as "evidence".