In message , at 13:23:53 on
Wed, 18 Apr 2012, Paul Corfield remarked:
The rules say
that capping aligns to the equivalent One Day Travelcard. I have
checked this against TfL documents that I have about Oyster ticketing
rules.

That's a plausible rule (a bit severe on people making just one trip
outside Z4, but that's another issue), but isn't consistent with claims
that:

"Oyster will work out the cheapest combination of fares for all
your journeys in one day."

.... which should be removed from the literature.
--
Roland Perry