I see it from the other side - I'm in a zed group that fights with the DHPD often. And maybe it's just a coincidence, but every time we clash the area is oddly flooded with chaff. The most recent fight, the DHPD pushed back into Dunnell Hills. At the exact same time, so did about three dozen level 1 survivors who had been created within 48 hours of the push. All of those ones I tracked died once and then went idle immediately. It was a pretty obvious speedbump tactic.