Here is my problem with contesting parking tickets. I once had a rental in Chicago (as I did not own a car at the time) that I had for a weekend. About a month later I got a parking ticket in the mail forwarded on from the car rental agency for parking in a no-parking zone. However, I never parked there, nor was in that part of the city. I am guessing the meter maid wrote down the wrong date or time on the citation as I was never there.
However, I was presented with two choices: 1) Pay 75 dollar fine 2) Take a day of vacation time to go to the city and contest it on a Thursday.
At the time, I made an after-tax rate of around 150 dollars per day. Even if I could do it in a half day, I am paying 75 dollars to possibly recoup 75 dollars. If I lost the argument, I paid 75 dollars to pay another 75 dollars. This is a real kobiyashi maru type situation for me, in which I just paid the ticket. It wasn't fair, it wasn't right, but it's the choice that makes the most sense.
I've also got a parking ticket that I didn't feel was just for being parked in front of a fire hydrant. That time it was me driving, however, I had pulled over to the side of the road to use my phone as I was getting an important call. While I was on the phone, (with four way blinkers on) a police officer came up and asked me to move, which I did. Before asking me to move, they took a picture of my car and sent in the ticket. This was completely legal (I was 'parked' in front of the hydrant), but completely unjust to me. Again, it wasn't worth my time to try to contest it. It was legal but unjust (in my mind)