Hello! I've been mulling over an idea to effectively report the various griefings found around the overworld. I figured out a way that may be a good way/good foundation for a plugin that would allow players to report many of them and possibly encourage them to report them this way more. So the way to do this would be to create a plugin that allowed you to obtain one of a few special banners that indicated a grief. The banner would then be placed down in or near the area of griefing to allow a staff member to teleport there at any time and take care of the situation. There would be a color-based severity indicator to indicate priority. Red for severe/recent, Green for badly damaged, blue for light griefing (few broken windows). Then there would be a category of them. Creeper for destruction/property damage, Bricks for block spam/overworld griefing. There are 3 special banners for special occasions. Pink/ Black X for Inappropriate, Distinct banner for Towny griefing (claiming around someone else's small build/in a build), and Shaded Creeper for Lag Traps (tons of redstone contraptions that do nothing, usually packed together). These flags should not be able to be taken down by other players, only staff members or those who have permission.
Players would do /Flag or something similar, which would open a chest with a selection of the aforementioned banners. They would place it down and the banner would appear so others can see. To prevent griefing with spam, It should be limited to one per chunk, with a 1 chunk radius around it where other flag banners cannot be placed. It would also help to make it remember who placed it in case of abuse, and if a staff member goes there and finds the flag to be accurate, the staff member will place down the confirmation Sun flag. This flag will delete both flags, and reward the player who flagged the grief with a rare candy (to encourage them to flag griefings). I think this is viable because I have seen similar and very impressive plugins implemented into the game. Here is a link to the banners I mentioned. Here.