I'm happy that Advance Fares exist as a strategy for managing passenger demand throughout the day, and meanwhile, they provide a lower cost of travel for those who can travel at those times.
But I have been consistently critical of 4 elements of the Advance system:
1. The Advance prices are used to increase demand on quiet services in much the same way as Off-Peak and Super-Off-Peak prices aim do the same thing; but the difference in T&Cs between Advances and Off-Peaks are unhelpfully different (e.g. it shouldn't matter to the TOC which of their few very quiet services a passenger has chosen if they have chosen one of them).
2. The gap between lowest tier Advance price and walk-up price is too wide. It can be around a tenfold difference. Flamingo's understanding that some pax would be shocked to learn the difference if travelling on the wrong service illustrates this. A narrower spread of prices doesn't seem to have any downside (if priced to achieve the same or better demand as at present) but does reduce the 'headline' prices and reduces the impact of silly errors (which seems to result in as much ill-will as Advances marketing aims to generate good-will !).
3. The fact that a passenger travelling on almost, but not exactly, the booked service on an Advance ticket will find that their ticket has no residual value offends my sense of an equitable transaction. The passenger paid for a ticket, the TOC is running its quiet-time-of-day services, there's really no need to charge a walk-up fare IN ADDITION to the cost of the unused Advance.
4. The promotional use of Advance prices has reached misleading proprtions (as I've often remarked on here). The widespread marketing of £15 Advancce tickets Newcastle-London can have escaped few people's attention in the catchment area. Perhaps it generates good business. The only 'small print / conditions' on those billboards, bus ad etc is (when you buy in advance). That's a small 'a'. The innocent buyer is not alerted to the distinction between the 'a' and an 'A', and nowhere, absolutely nowhere in the booking process is the buyer warned that if the travel on a similar but different train then they will be asked to pay more; that 'more' is likely to be 10 times the amount paid; that the amount paid will not be offset against their cost of travel. I have other concerns about misleading advertising, just 2 of them are the claim '£nn from A to B' which may not in fact be available from B to A on the same day as those A to B fares are released, and the '£nn from A to B 10,000 tickets released every week' when those two statements have no connection in fact.
In short, Advances have a useful function for the TOCs and offer a useful benefit to passengers; but I abhor the excesses of their marketing and am unpersuaded that their regulatory framework is the most appropriate to achieve their purpose.