The problem with this, though, is that win trading is not allowed.
As confirmed by senior GMs, win trading is not only investigated by reports, but Account Administration actively hunts down teams that are win trading.
Yes, i know it isn't allowed. If you are afraid of being caught, go to the blades edge arena or something.
My friend has been doing this for months now, and he haven't been caught/reported once.
One of the reasons blizzard does this except for the arena team reason is that they want to have control over the trades and easily know if it's gold-bying-related stuff going on...