I'm not going to contribute to my friend's parking ticket
Why is that even an issue?
I don't care what the police do.
Paying for fines is something we all have to do, it is important that we follow the rules. It could get you in serious trouble if you don't do what is right.
It's my friend, I won't help.
Did he request help? If he's usually responsible and will pay you back, you should help him.