That makes since.
Let's change the scenario. Let's say you're at the mall. A cop, who is not scheduled for mall duty just finished up with an earlier situation and is preparing to leave. Now, the posted speed limit is 15 mph and I'm doing, say 20 as I drive by the officer. Can he stop me and issue a ticket? If so, can I contest it in court? Remember, this all takes place on private property...