Anyway the whole Oyster system is just a scam to screw as much money
out of people as possible with the debatable sweetener of slightly faster
I realised breaks of journeys get charged for but on the rail system using
paper tickets it's acceptable to break journeys without extra charge (and
why not?).
Cockfosters to Heathrow is £2 but go out and come back in at Covent Garden
and it's £4.
Sure it's their ride and if you want to use it you have to pay what they
ask - but the cost of carrying you on both journeys is the same (except for
a bit of gate-wear as you exit and re-enter!).
Shame the cost never relates to what you pay
Cheers,
Dave