John B wrote:

But Guildford - Portsmouth is not covered - and indeed, the list of
stations you *can* travel between is almost the opposite of the list
of stations you would find if their primary aim was purely to fill
empty seats with cheap tickets and not abstract revenue.

Rather, their aim is to do that as much as they can /without imposing
any additional costs on the business/, and that is what determines the
stations they're serving.

Agreed. But I think the price discrimination rationale explains why they
would be annoyed if someone followed the advice you gave upthread.
--
Michael Hoffman