Or the simple answer
ban mainland China
I like Postal 2 and Metal Gear Rising.
JP legit banned China from the game and has seen a massive decrease of Ad bots since, NA is basically a shit show of wild west proportions. You can't tell us barely anything can be done about it when little to no effort has been put in from the NA side of things, I don't know how long it took JP to ban China from the game but that's where almost all of the reseller's site domains are located.
You ban China, you get rid of the bots.