From what I read in a few months they will allow guild name changes for rl cash.
Well I was able to have both guys turn the GM to me before I gave then the gold, as I could show them I am a "known" player.
Once you have the title its hard to lose it if you don't touch the guild bank or kick anyone from the guild, or do something against guild interested, if no one complains you are OK.
You can't really get scammed unless of course you hand him the gold first and he dosn't give you the GM title. Make a lot of Screen Shots.
Because its not against the ToS Blizzard should be able to help you out if there is a scam involved but I wouldn't count on it 100 percent.
Connect With Us