They are dealing with bots. Otherwise the game would be completely unplayable without trading retail gold for classic. The prices of many things clearly show that they are dealing with bots, except they don’t deal with them immediatly. Some say it’s because of something called subscription refund window, others say it’s because they want to do more than just ban the accounts(they have relationships that need to be dealt with as well).
Trading retail gold for classic is perfectly fine according to this reputable source(I mean it’s still up so surely they’d address the thread if it wasn’t):
That said classic is a publicity stunt, and adding a token would not do a great job keeping people from going back to alternative servers out of principle(ingame shops, tokens ruin the overall feel of the game).