It's a direct response to De Blasio's asking police to implement Broken Windows policies. They are sending him the message they aren't taking his orders anymore.
Which, to me, is the scary part of this whole thing. Before, it was only implied that the police weren't accountable to anybody -- now they're literally turning their back on the head of the municipal government.
Police is still accountable and are doing their job. If anything the extra 'cash' they generated was a 'favor' to the said municipal government.
They are actually doing you a huge favor. No more bullshit tickets at the end of the month.