We can't know for sure, but SE has already shown what it will do in other situations:
- Player A crafts or gathers high-demand item and puts it up for sale.
- Player B presumably buys RMT gil and uses that to buy Player A's item from market board.
After a while of this, SE notices Player A's large amount of gil, declares it "dirty", and confiscates it all. Player B keeps the gear and keeps playing.
In short: don't expect "fair". Expect autocratic. Hope you don't get noticed.
