Some more random ideas, some of them may hard to implement
Clown Police - Give everyone random primary & secondary colors (Optionally accompanied with a short circus music, feel free to DM me for a sample if we're going through with this)
Blind Cops - The cops' screen turns black for 30 seconds, with the HUD still being visible.
OHKO - Crook & Cops have a collision damage multiplier of 100 for 30 seconds.
Crook POV - Cops see the camera from the crook's POV for 30 seconds, like they do after they die. Their radar blip stays the same and they can move their vehicles.
Pole'd - Spawns a breakable pole in front of the crook