Talk to your government and have them pass a law that the buyers of IG currency will be prosecuted.
1st offence would be 3 months Community service and fine of $1,000 online service account cancelled.
2nd offence would be 3 month jail time with no internet access. $2,500 online service account cancelled.
3rd offence would be 1 year jail time with no internet access, fine of $5,000 online service account cancelled.

Where if games have issue with RMT they are required to forward on transaction info to Government to take action. IE User contact info of who got the currency.
Government only takes action on 2nd report of same user to make sure it's wasn't a one of or mistake.

SE could make RMT script to weed who they are. And who they sent it to. The buyer should be punched as my as the seller.

Make it part of any new LOOT BOX LAW.