Them hiding the rest of the clip is a little bit suspect and shows that they believe they were in the wrong.
The entire day they were sort of trying to bait a little bit of a conflict and waiting for people to bite, they arrested them for walking in front of them.
In my mind it's a bit like mugging someone knowing they'll retaliate to bait for a PK. Sure, they know that someone has the ability to not retaliate but often they will, it's the exact reason why mugging cops and PKing them has become virtually non existent whereas it used to be fair game.