On Feb 19, 5:56*pm, JS wrote:
System has no way of knowing whether journey was started within zones
of Travelcard or beyond, hence the charge.

The point I was making is that *wherever* you started your journey,
the "maximuum" fare you could possibly pay is that of the zones not
covered by your Travelcard, and IMHO that should be the penalty. I.e.
Given a z12 Travelcard, if you actually started your journey at
Canon's Park, but didn't touch in, being charged as having come from
Willesden Green would be the penalty. The principle should always be
that there should be no requirement to touch in within the zones where
your Travelcard is valid.

Equally - the mixed travel maximum Oyster fare is deducted when
touching in at a station outside the zones of your Travelcard.
The system has no way of knowing whether you will end your journey
within the zones of the Travelcard.

This is more reasonable, after all it's the start of a normal PAYG
journey and you may as well keep it consistent. IMHO, it should still
deduct the zones you have a Travelcard for though from what it deducts
upon entry though - after all, you've already paid for them.