A bit of advance warning for those who haven't heard - from November,
if you use pre-pay Oyster, and you fail to touch in or out at any point
of your travels where you're supposed to do so, you will find yourself
being charged £4.00 for the incomplete journey.

In addition to this charge, word on the street is LUL ticket offices
will be unable to adjust this (as they can now), and you will have to
call Oyster Helpdesk (which, like most call centres, can often mean
sitting on hold while you could be doing better things).

Just so you know.