International criminals will be delighted
That is all.
Mastercard is opening up its blockchain API to select partner banks and merchants. For those approved for sign-up, Mastercard boasts that its tech will improve "cross-border, B2B payment flows". There are tons of blockchains out there, and Mastercard isn't the first enterprise actor to work on a B2B distributed payment system …
IMHO Mastercard being a terra firma entity then, if it is their Blockchain surely they are obliged, on demand, to reveal transactions in there, and show what due diligence they performed in order for any transaction to be stored. In other words, standard money laundering checks for transactions entering or leaving the Blockchain.