The people that get banned from GB

Is it because they only gather in mists of pandaria would it be safer to farm in an area like catalcysm?

 

Nowhere is safe, its pretty much determined by how long they bot, the system might pick up some stuff and if they get reported by others or not.

 

As karl said, its pretty obvious, the Blizzard have implemented server side scripts, which flag accounts by certain criterias, probably by time spent, doing bot-like activities like gathering herbs/ores, and they compare this time to the time, spent on the account for doing not-bot activites, like running dungeons, lfr for example.