Fighting it is a risk. Basically, the cop usually doesn't show up, but if he does you probably won't win. That being said, everyone I know who faught it has won. I have usually bad luck though. Someone reported that I hit a car in a parking lot, backed up and then drove off (the women who reported me didn't own the car), cops even came to my house (though I was still in the area shopping). Thing was, I got out of the car, checked, went into a store (I had a receipt to prove it if they had wanted it), and then left. I saw no damage, the cop agreed that I had seen no damage, saying he used a flash light and then ran his hand over the spot before he could feel a few bumps. Insurance went up.
Next time I got pulled over for doing about 50 in a 30 on my way to school (I was late and there was some reason I needed to be there, I normally didn't care when I was late). First time I got pulled over, and I appeared completely confused. Cop was nice and gave me a warning. Though I think he had to anyway, he didn't have a speed gun when I went by. I kept saying I didn't know how fast I was going (which was true, didn't know exactly), and kept saying probably 40 (after 10 miles over it goes up 10 bucks a mile). He kept saying it was faster, but that's all he wrote on the warning. No increase.
Third time I ran a red light while looking for a store, when I saw it I stopped. Saw the cop car sitting there, saw that I couldn't stay in the middle of the road, then continued slowly waiting for sirens. Cop took my id but came back a minute later saying he had an accident he had to get to, so nothing there. No increase.
Fourth time I got a ticket for going 76 in a 65 on the new york state thruway. I would have fought that one, but I didn't feel like driving from boston to syracuse. After later trips I realized NY is a lot different than MA north of boston and NH, where people regularly go high 70's without catching a cops attention. The NY thruway is swarming with cops. Insurance went up.
Fifth one was I was going 70 in a very light rain on the new york state thruway. I started passing a truck (didn't increase spead), and the car spun out in the left lane, first hitting the rail on the right side then stopping when it hit the left side. About 6k damage (insurance covered), though nothing in the car was affected, besides I spilt my coffee (my pets and myself were fine). Not my fault, insurance went up.
Sixth time was I had just found out my friend was seriously thinking about joining the army. When I dropped him off the whole time home I was thinking about what could happened if he joined, him getting killed etc., so I was out of it. Anyway, cop pulled me over claiming that my tire drifted into the breakdown lane, and then the left lane. No one was around me at the time. The cop even told me I could fight it. I would have, but that was december 30th and I was going back to toronto Jan 2nd, so I wouldn't be there for the court date. No one can believe I got a ticket for this. Insurance went up.