My answer to this is always yes. It's best when the camera is conspicuous so that it deters this kind of behavior. It won't be perfect, but running a camera and not needing the footage is far better than not having a camera when the footage would've been needed.

Below is a personal example of harassment from teenagers. On this group ride the kids in question threw trash at both my group and the one behind us (out of sight on a previous road). No one in the other pack had a camera, but luckily I did. Since the juvenile court system is tight lipped, I don't know the ultimate fates of these teens, but I do know the detective recommended assault charges. Regardless of the criminal outcome, the social fallout was pretty heavy. One of the friends I shared the video with has a daughter who went to the same school as the offenders, and all of them (including my friend's daughter) were on the wrestling team. The video spread like wildfire throughout the high school, and the perps were made fun of relentlessly by their peers.