In article ,
Walter Briscoe wrote:
It won't address a short stay at Finsbury Park where each validator
heuristically distinguishes entry and exit in the absence of gatelines.
1) Touch in at any station - e.g. Manor House;
2) Touch out at Finsbury Park;
3) A touch again at Finsbury Park WITHIN 30 MINUTES is a touch out;
4) Touch out at the same station as 1). i.e. Manor House.

ISTR you are charged for an unfinished journey and an unstarted journey.
Oyster has no automatic mechanism to recognise this.

OTOH, Manor House via Finsbury Park to any other station, e.g. Arsenal,
is charged correctly.

This seems to be a FPK peculiarity. I found no problem at Mill Hill
East. I haven't tried at Waterloo on the W&C or at National Rail
stations which don't have gatelines.

Are you sure? I thought I'd done this at FPK without mishap, but
maybe I was there longer than 30 minutes. But I think the validators
display 'entry' or 'exit' when you touch, don't they? -- so if you're
watching you'd at least know whether or not it is trying to do the
right thing. If attempts to touch in show "exit" I'd probably attempt
to 'seek assistance', as they say...

I thought if you touch twice in a _very_ short period of time it does
what you say -- presumably to avoid problems due to accidental double
touches -- but I didn't realise it did that if you were there for any
substantial period of time...

-roy