This seems a bit unfair to me as it effectively penalises the retailer for what are in many cases the station operator's problems.
Indeed; in this case I believe Chiltern will be charging LNER something like 50p (?) for these tickets to be collected.
LNER probably aren't that bothered as they will be charging other TOCs, in one huge merry-go-round of charging.
It's third party retailers who really lose out.
If e-tickets are available, I would recommend people use those. If anyone wants a physical copy, they can be printed. If travelling as a group, you can give each person in the group a copy of the tickets or email etc (when I go abroad it's very common for tickets to be issued as e-tickets and I often book for a group and give everyone a copy of the tickets)
With paper tickets, there is the faff of collecting them and if they are lost or stolen then the customer has to purchase replacement tickets at their own expense.
If the TVMs are not working and there is no way to collect a ticket, the customer must be allowed to travel and, if subject to a ticket inspection, can simply quote their TOD collection reference number. The tickets can be collected en-route. However not all train companies follow this procedure and there have been some reports of forcing passengers to buy replacement tickets and seek refunds, which is not correct, but it does happen occasionally.
Sometimes a TVM will get stuck printing tickets; in this case the procedure is for any relevant ticket office to re-print the tickets but in practice this rarely happens and passengers can be sent back and forth between TVM operators and retailers (see this thread:
https://www.railforums.co.uk/threads/tod-collection-problem-return-portion-not-printed.189276/ )