There are two reasons servers get blacklisted:

  • Faking Population
  • Illegal Plugins within Community

Facepunch are very fair with their rules for running servers. You’re allowed plugins which don’t modify the native aspects of the game. This means things like AdminRadar and Vanish are allowed because the base game remains the same. Please see Plugins under Community Article for more information on what is and isn’t allowed.

You can find out which servers are blacklisted at this URL If you use firefox it’ll give you a nicely formatted JSON file which you will be able to search within.

Faking population will lead to an automated timed ban on the first instance.

Having illegal plugins within community will lead to you being blacklisted if you are still doing so after being warned/contacted previously.