That's why the recommend going to contest your tickets even if you are fully guilty - if the accusing officer does not bother to show up, you automatically get the ticket tossed.
That's not always the case. I got issued a speeding ticket in Washington over a decade ago. I was given the same advice regarding the officer needing to be present, so I went to court to contest (since I felt I was simply matching the speed of everyone else on the freeway, but was singled out). When I got to court, I was informed by the judge that the ticket (and the writeup) was the only evidence needed; the accusing officer did not have to be present. He read the ticket out loud for the court, which included the other point I was going to bring up to try to weasel my way out of the ticket: if he calibrated his radar gun before and after his shift. He had.
Luckily, the judge gave me a break and waved the ticket due to a paperwork technicality he could have kept to himself if he really wanted to.
Not without a reboot. The values are set at boot time, and the specific file for Ubuntu 9.10 + Wine is
You could always reset it by hand if you don't want to reset by using the method described earlier.
Numeric stability is probably not all that important when you're guessing.