In message , at 17:45:25 on
Mon, 9 May 2016, Paul Corfield remarked:

an hourly cap works *provided* you don't care about whether people can
make a return journey for a single fare within 1 hour. If you do care
about that then the checking logic becomes very complex indeed.

Notwithstanding you go on to say some administrations seek to ban that,
I doubt if the Mayor has mixed such a thing into his promise.

The only place I recall permission plus a limit (maybe an hour, I don't
remember) on multiple trips - which includes their Metro as well as
buses - is Brussels and I don't think that has an anti-return or
anti-circular-trip mechanism.
--
Roland Perry