Just get on your bike, ride up to a cop car (or any car) and jump just before them, roughly so your front tyre hits their window. It smashes, and your trouble meter remains on zero! Just be careful not to 'stop' in front of the cop car, then it can say 'obstructing authority' and you get some trouble meter. but that's ok yo ucan just throw crackers to explode in their face and slingshot their heads before running back into the dorm.