Solar Penguin wrote to uk.transport.london on Sat, 12 Feb 2005:

Suppose you want to travel, for example, from Crystal Palace to Oxford
Circus. Why can't you simply buy a cheap day return from Crystal Palace
to Oxford Circus? Instead you *have* to buy a One Day Travelcard for
zones 1-4, which means you're also paying for the flexibility of
travelling to Morden, Mill Hill East, Waterloo, and dozens of other
places that you won't actually visit today!

Why? It is probably cheaper (almost certainly, if you have Pre-pay) to
buy a ticket from Oxford Circus to Brixton & then take one of the 3 or 4
buses that go from there to Crystal Palace, and reverse it. There is no
obligation on you to buy a Travelcard if you don't want to.
--
"Mrs Redboots"
http://www.amsmyth.demon.co.uk/
Website updated 23 January 2005 with new photos