What if I didn't have any prepay, but just the travelcard? Touching in
and out would never relate to my credit being charged, because I
wouldn't have any.

It's impossible to have a "prepay-less" card. Even if your prepay
balance is £0.00, you can still use prepay, and your balance will go
negative.


I thought I was confused, but now I'm not sure ...

I've never yet put any prepay on my Oyster, and I can't remember what
personal details I gave, although I didn't prove identity or anything.
It would seem odd if I could now run up a negative balance, but maybe I
should try.

I think the thing that generally bugs me is that while unstaffed or
ungated stations, or particularly determined evaders, exist, it is
possible for people to travel beyond their zones or without tickets,
and they may occasionally risk getting "caught".

But all the discussion has implied that someone who does pay TfL a load
of credit and makes an attempt to get it deducted by touching out at an
unstaffed destination may get clobbered by the Oyster system due to
something they didn't do earlier, while someone who just wanders out of
the station with no ticket or prepay credit won't.

Why the extra burden of accusation and punishment for people who pay in
advance and make an attempt to debit their balance? This is perhaps
the nub of the kernel of key to the problem I am having with all this.
It's what I previously meant by "an artefact of Oyster".