@Tascha
This if people see that people are being banned for building under mesh or expolioting duplication or extreme grieffing of a server if will cause others to think twice before they do it and wear it like a badge of honor and admit to it in general chats.
For example at login screen could have a section of:
This week we took action on players for
Expoilting building under the map: 10 players
Grieffing by blocking spawns : 8
Duplication: 5
Etc…
Then just update it once a week.