MWhat amount? And how do you communicate that person A only needs a code while person B needs the barcode, even though they didn't need it last time they travelled? Can you not see how much confision and difficulty this would cause?
Not really, no.
Very few people ever find themselves in a position where they can show the reference number but not the barcode, since they receive both together. So it's hardly a floodgate everybody's going to surge through once they hear they don't need the barcode.
You could argue, therefore, that it's a non-issue, but what I'm saying is the negative publicity it can cause when it happens is out of all proportion to how rare it is. And when somebody paid £200 for their tickets and the story gets written up in the paper, it looks very bad.
So you don't change any rules, you put out industry guidance to waive the requirement to have the barcode where customers have paid more than, say, £50 per passenger per journey leg and the ticket can be verified another way (but they should be told they need the barcode next time and they risk being charged extra if they don't have it).
I can't see this is more confusing or less practical than the internal industry guidance on starting short on advances, for example.
Another reason
So a fully loaded nine car 801 (611 seats) arrives at Kings Cross, to find the gates in use and everyone only having the UTN rather than the barcode. How long is that going to take to clear with manual checking? (And updating the e-ticket Validation Database to mark the ticket as used)
Everyone? This is a wholly imaginary problem.
If I'm wrong and it's a real problem, the obvious solution surely would be for whoever first performs a ticket check (which absolutely shouldn't be the people at the gateline at the train's destination station) to print the barcode for the passenger once they've verified it.