No worldguard more! This will prevent any griefers or someone else, to destroy your blocks! It woud be autoprotected by the server and protect the block! You can make cityis with plots to a less problem! Example: Ive made a town now.. A guy ask for a plot! The plot doesnt need to be protected by "worldguard". I can just simple start to build there without any protection by worldguard first! I can build there without any can come and destroy. Ideas for the plugin: A message pop up for the block that tryes to get breaked, by an other guy: Blockowner [name] to know who placed it! Please make this plugin! Many servers want this!!
This will mean you have to record every block placed by a player. And every time a player breaks a block it has to look-up that block and check if the player has rights. Also, how would you do collaborations then? Set permission per block?
