Not new, only extended: the exporter half has turned on who had the power to decide for years. The email is closer than the contract. On my floor nothing leaves without a release instruction, and whoever sent it decided.
You are right and I had it wrong, so let me say that plainly before anything else. I went back and read the export side properly after your reply. The power to determine has been sitting in that definition all along. What fell away later was the condition about holding a contract with the buyer abroad, which is your point about the email being closer than the contract, and it fell away years ago. So what I read as a new test is the old export test walking across to the import side.
The release instruction is the part I want to take away, and it is also where I get stuck. On my floor the instruction that starts a movement comes from the customer abroad. They pick the window, we book, we drive, we store. If whoever sent it decided, then the document names somebody who is not established here and cannot hold the role at all, and the question turns into who stood in for them and on what authority.
Which would make the file two documents rather than one: the instruction, and whatever says we were empowered to act on it. Is that how it reads on your floor when the sender sits outside, or am I building a file for something the paperwork already answers?
Not my code, so take this as a contrast, not an answer. Here a customer abroad cannot be the party of record at all, so the question you ended on is settled before the truck loads: somebody established locally is named, and the mandate to the broker is registered and has to be accepted electronically before anything is declared. Your second document exists here as that acceptance, not as an email. It costs the broker plenty: joint liability for the accuracy of what is declared, and the licence behind it. Setting one up takes days. A hold takes weeks.