I have an idea for a command that would help people that are annoyed by others. How about a /ignore command? Example: If a player does "/ignore <PLAYERNAME>", the player that he/she chose to ignore cannot be seen/heard by the player that is ignoring them. Also, the player that is being ignored also cannot build on the ignoring players plot(s). I think this would be a great idea for a command. (Also, the player can stop ignoring a ignored player by doing "/ignore stop <PLAYERNAME> (Just noticed its already a command)
You can just remove the player from your plot (if he is added), and to ignore what they type just do /chat ignore <player name>