Cops should stay and not run away from a criminal who was ticketed by them - that's a rule you can find in /coprules
However, you are not allowed to block them from running away in any way, the only exception is when they are driving stolen vehicle. You're supposed to tell them to pull over, that's how will they will get 2stars before the ticket expires. On top of that, blocking them from the escape using your own playermodel, which can cause them to go from 1star to 6star is called baiting, and is not welcomed.
DENIED.