The problem is in RL if you are a merchant, hell even a consumer, you have ways to verify your "money" is valid and not counterfeit. There are generally errors on it and also we use bank debits cards and there are devices to detect fake money etc etc.

In game though there is NO WAY TO VERIFY if the purchaser is using fake/stolen etc money its a complete russian roulette game. It is therefore up to SE themselves to give us a way to make sure gil used in such transaction in the AH is "good" especially if they will hold us responsible and take the money we earn away at a later date.

I mean there's still rmt spamming and therefore I am sure still people buying gil so what is the point of trying make money other than by quests/levee if at some later date it will be taken from us?