Knock someone out, either with zombies, or bullets. And the server will crash within a fairly short amount of time. They might need to die, so, a horde of zombies, or shooting someone, then they die soon after. (Or hit the respawn button.)

My buddies and I have been playing quite a bit and, this has been observed VERY often. It's frustrating when we knock someone out, and go to tie them up/heal them for lols and memes and maybe let them go later. Or just steal their pants and run away. But it's very persistent. We do NOT play on a modded server.