"But to go without a ticket you get a QR code."

This is in part why I'm confused, since you said he didn't actually need the QR code to go without a ticket.

While we're here, let's raise a related issue.

To enrol on 12306 so you can travel by face recognition, you need to submit a photo of yourself with your passport, the same passport registered to your account, of course. But if you opened your account years ago, you'll probably have a different passport number by now.

This isn't a problem buying a ticket, since you can easily buy a ticket for another person, who happens to be you with your current passport number.

But it is a problem enrolling with face recognition, since the system doesn't allow you to change your original passport number. Opening a new account is possible, but not with your existing mobile number since it's linked to your original 12306 account.

Anyone else faced this problem and resolved it? I've thought of contacting 12306: don't know if that ever helps.