City wants money. If it isn't this person, then the chance of them getting money goes way down. So they have a perverse incentive to force this person to pay,

City wants money. If it isn't this person, then the chance of them getting money goes way down. So they have a perverse incentive to force this person to pay, regardless if it is them or not, as long as the person isn't willing to fight a legal battle that ends up costing more money (if few enough people fight the legal battle, it may be more profitable to let them win their fights and keep charging all the people who don't fight). This is the problem letting the same the same entity that decides a punishment benefit from that punishment.