Last week I had call to make a journey from Sudbury Hill to Kings Cross.
There are two options for making this journey

1) Take Piccadilly Line East to King's Cross. Zones used 1-4
2) Take Piccadilly Line West to Rayner's Lane. Change at Rayner's Lane
for Eastbound Metropolitan line service to King's Cross. Zones used 1-5

Route 2 is the one suggested by TfL's journey planner and is typically
slightly faster.

As I have a 1-4 travel card I would typically use route 1.
However occasionally (if there are problems with the Picc in the central
area and/or if I am in a particular rush) I might decided the extra cost
of going through zone 5 is desirable.

In the years before oyster I did this by extending my 1-4 season ticket
to include zone 5.

However I now understand that the Oyster Pre-pay[1] mechanism replaces
season ticket extension (that is what a ticket office person told me
anyway - not on the occasion of the journey in question admittedly).

So I went through zone 5 on this occasion but was not charged the extra.
Whilst I am obviously happy to save the money (and am unlikely to
proactively pursue TfL to give them it) it does occur to me that this
could be seen as fare evasion.
So what should I have done differently in order to avoid evasion? Were
there some within station Oyster touch-plates at Rayner's Lane that I
missed?


[1] Rather a silly term - I'm not sure I have ever encountered a
post-pay rail ticket.



--
Each day a man watched a donkey walk past a high wood fence with one
plank removed. Each day he saw a nose, then the ears, then the neck,
forequarters, back and finally the tail. He pondered this for a time
and eventually declared. “I understand now. The nose causes the tail”