found one of these people harvesting under the world tonight. by luck there were very few people in the zone at 4am and I used a /target macro and did that for the 3 other people in the zone at the time. low and behold I ran into one of these nodes that was already being harvested. used my macro and targeted said player. (keeping that players name off here as its probly against the rules to post that here) I petitioned it and hopfully the GM does do somthing about it.
If there arnt many players in the zone and you cannot track you can do the same works great. the arrow that targets the player was halfway under the ground. (the player was also anon you can probly narrow your /target macro that way most likly most people if not all people who do this are anon)