If you have evidence that points to a fault in the system then present it, definitely. Your job is at risk here and you need to stand up for yourself. However, at this stage i would advise against mentioning other colleagues mistakes which have been overlooked, unless they directly affect your situation.
If I parked on a double yellow line next to many others who didn't get caught, it doesn't excuse me from doing it. Just bad luck. If however the lines were really worn and there were no notices up, i can argue that the system is at fault.
Good luck