How can people making multiple reservations be managed?

[Bletchleyite]

Cancelling reservations is absolutely what I have in mind. As for edge cases like seasons or rovers, I should define my terms more precisely - the restriction should be on the journey so that no more than one* is held between the same station pair on the same day. It won’t be perfect but very few people will find themselves making repeated journeys between the same two points.

* - before someone asks, I’m reservation means an individual or a set of reservation or set of reservations on the same account.

Separating this out as I think it's a worthwhile discussion.

To me it would make sense to move towards having a "GBR account" which would hold your ticket and reservations together (and could be interfaced with by third parties). So if you wanted to change your reservation on a walk up ticket you would just press the "change" button and make a new one, and as you say you could only have one per ticket, you could also cancel it completely on a walk up leaving just the ticket. I think Trainline has actually already implemented something like this to help avoid the complexity of when walk up tickets are valid and when they are not.

Once we move to fully barcoded ticketing it wouldn't be hard to manage this at all points of sale based on the ticket number which is fully unique on these unlike on traditional paper tickets.

This would remove the ability to make pre-emptive reservations without a ticket, but I don't think the railway really wants these to be possible anyway, they just are because of technical limitations (i.e. there's no way for LNER for instance to know if you enter a random 5 digit number whether that's a ticket valid for that journey or not). Traditionally a booking office would only make one for you if you showed a ticket or purchased one at the same time.