Mizter T wrote:
Though in the last example you only paid FCC for *part* of your journey
- the Moorgate to Finsbury Park portion. The Oyster system would have
allocated the rest of the journey and hence the rest of the revenue to
LU for a Piccadilly line journey from FP to Bounds Green. The Finsbury
Park to Bowes Park portion of your journey on FCC was therefore not
paid for.

Why should it assume I used that line at all? I might have taken the
Northern Line to Kings Cross then the Piccadilly Line from there.

And if I have an Oyster season, how would it allocate that?

What might be useful, but I don't think it happens, would be that if
you buy an Oyster Season ticket which would have covered any journeys
you have already made that day, those journeys are automatically
refunded. eg I get a bus to the station (paying £1) then buy a season
ticket, the £1 would automatically go back onto the Oyster pre-pay.

That would have solved the problem of the journey from Pudding Mill
Lane to Canary Wharf, where I could have touched in and out, and
subsequently had the fare automatically refunded when I bought an
Oyster season later the same day.