It's clear that TfL has no intention of stopping people from combining
Travelcards held on Oyster with paper tickets for journeys beyond the
zonal validity. Inevitably the inherent presumption is that those
using a Travelcard loaded on Oyster who wish to travel beyond the
zonal validity of said Travelcard but still within the London zones
will make use of Oyster's ability to combine Travelcard and PAYG in
order to automatically pay the extension fare.

The one significant group of people who may have other ideas is Gold
Card Travelcard holders (i.e. annual Travelcard holders), who are
entitled to a third off fares (like a Railcard) but cannot have this
discount entitlement activated on their Oyster card (unlike holders of
Railcards, except the Network Railcard and Family & Friends Railcard -
the latter at least being an understandable omission). As to why this
is the case, you would have to ask ATOC and TfL!

Also, just to make life interesting, the NRCoC does also mention that
usage of electronic tickets is subject to their own conditions of
issue and use! If the two sets of conditions (NR and electronic
ticket) were really in conflict, which would have primacy is an
interesting question. One rather suspects that those parties involved
will work to avoid that situation arising.

London Travelwatch are to discuss some of this at the February Fares &
Ticketing meeting.

The documents include a list of gated and ungated stations.

http://www.londontravelwatch.org.uk/...ent.php?id=687