GDKP Ninja, Banned!
A recent GDKP TOTC25 run in my server turned out to be a very disappointing ninja run. At the end of the raid, the raid leader went offline and never returned. Of course everyone got pissed and started opening a GM ticket to report the incident. A friend of mine who was part of the TOTC25 run said in the ticket that a GDKP ninja is considered an in-game scam and should be punished accordingly. Furthermore, he stated in the ticket that if Blizzard turns a blind eye on the GDKP ninja, they are allowing scamming and possibly RMT. The GM replied that the ninja would be banned and all the gold would be returned to the raid participants (sorry, no screenshots).
From this story a successful punishment for GDKP ninjas are reports from most raid participants and a detailed description of what happened. Furthermore, a professional letter to the GM is most advisable. No “OMG PLS BAN XXXXX HE NINJAD OUR GOLD IN GDKP RAID. BAN HIM NOW” would be successful. Stating the situation very clearly and formally will help the GM figure out the incident and take action as quickly as possible. State the date and time, what raid, the name of the ninja, how much gold was taken (if possible), and give a very good reason why the ninja’s actions should be punished (e.g. scamming, possibly RMT, etc.).
Future GDKP Ninjas be warned! You will be punished!

