its a the biggest issue of multiplayer right now period and should really be the developers main focus, not even a debate
as you can see from many other posts on here and player complaints, exploiters/hackers have been causing havoc every server, you cant kick them as you cant really tell whos doing it, and im pretty sure some of them dont even need to be in your server to do it
the things they can do are listed here (and thats just the start)
spawning any item they like anywhere on the map (ive gotten gigantic N words and explosive lag cubes)
crashing servers instantly
changing scripts of chat mods to make players say vulgar things