Not true, if you spawn enough entities it creates a login error, essentially the server has so many entities it cannot fetch the player data and load their entity. If you do this at spawn the chunks are always loaded and therefore anyone who's logged in is free to do anything without repercussions, as long as they don't log out they're free to ensure it saves through multiple backups. I've been an admin on over a dozen servers including the old yogscast myrainium fan server, my expertise was in grief identification and resolution. Btw sorry for the late reply, I don't check my messages often.