So for the LEOs in our midst.
From the original news article should this have been approached in the manner I am about to describe.
Since it seems the LEO had no reason to pull over the biker for an offense, he should have pulled the biker and told him that he was not being pulled for a crime however he was informing the person that his camera would be sought by police for the footage it contained. Then take all of the rider's pertinent information for records to ID him and issue the subpoena.
At this point if the rider/camera owner deleted footage or never responded to the court order then they could issue an arrest warrant for obstruction of justice (or similar).
From what I can tell in the news article the officer had no legal reason to pull the rider except to get the footage; especially since he went back to his car for a few minutes before coming back with the obscured plate charge (which i though was mainly a "fix it" ticket).