One of the main features of the upcoming
Minecraft 1.4 update is the inclusion of modding API for servers, which means servers themselves can host respective mods which will be automatically downloaded by players upon joining the server. It makes playing on modded servers significantly easier for players around the globe, and allows for mods to spread around to different servers more easily.
(Source
http://gamerant.com/minecraft-1-4-details)
Clank could make a mod that checks for hacked clients and if a player have one, they'll get kicked. (Hopefully)