The YJ bots you see are not the source of money of the RMT trader in the WC, they are just diversion to make people think the RMT is getting it's money from the bots.
The Real Yuan that is being sold are generated by the GM's themselves and is sold in the WC thats why they don't ban it and if they ban it takes weeks and another one will appear.
Botting will not generate money up to 1B yuan it is impossible try do the math yourself. I have tried it myself my lvl 50+ YJ can earn only max of 200-350k in a day of botting 8-12 hours.
The game company is doing a psychological way of decieving the buyers, since players would shy away if the price of gold is high and rather not buy, but that changes if they can see an advantage such as what you see in the WC selling cheap YUAN.
For the consumer to consume and spend to the maximum. There must be competition between a high price and a low price in the game, so the game company itself makes a virtual competitor that sells yuan at a cheaper price but in reality that competitor is also them. lol
And BTW those bot are made by wanmei developers themselves.
there are some version of it that leaked out in public but they are in chinese. It is hard to convert them w/out the source codes. 
How do i know this? i know some of them
they are my friends they are now not part of the company so they decide to tell me what's going on.
uhm...w/ many vendors?
