Whilst some games may not allow direct trading of goods (discounting the fact for now that some others do), there is a thriving secondary market in already built up accounts, with high level existing stats and expensive items on those games.
It's quite plausible that an account could be set up using a fake email and 'built up' to a high level using funds from a stolen credit card, then sold on to an unwitting buyer via a secondary market place. The scammer pockets the real money and the account is then transferred via giving the buyer the login to the dummy email address...not rocket science.
Take a look at https://www.g2g .com/ or https://www.playerauctions .com/ if you don't believe me.
ISX providing ID/KYC verification in this circumstance would be extremely valuable to the gaming companies.