And BTW, good luck taking your payment protocol receipt to court when the merchant claims you didn't pay.
It will work for the same jurisdiction, but not cross-jurisdiction. It could even be such that a merchant has to automatically acknowledge if a payment was received via the public blockchain. One example implementation would be forcing the merchant to use a certain address which is attached to the name (the merchant wouldn't be able to generate arbitrary addresses). In effect that's what the DAC/smart contract ideas are about. Registering a corporation is equivalent to assinging a payment address to a legal entity. A limited liability company is in a sense nothing else than a restricted account. Some of this can be implemented today, but I very much doubt that Bitcoin is going to be the system doing this (i.e. anything interesting in the future).