To be honest, I've been noticing this glitch more than I've been noticing boosters.
I've been playing Bo2 because I haven't gotten ghosts yet (I will be getting it later this month.) Bo2 has been getting kind of difficult to play now that ghosts is out and since we haven't gotten a patch in a while.
I'm not really sure how the guy was able to do the glitch, though I did notice the tac insert that was mentioned. I was able to shoot him when I was outside standing next to the building, but I wasn't able to get a kill off of him, just hitmarkers.