On Jun 18, 11:24 pm, wrote:
I buy a card for 3 quid + 1 quid value. Go through the gates to DLR or
NR station with no gates.
Come back the same way and touch out at my station. 8 quid gets
deducted so card goes
negative (gates always seem to let you out no matter how negative it
goes as long as its positive
to start with), would have cost 5 quid even if I had touched in /out ,
I paid 4 quid. 1 pound up.

Bin card, rinse and repeat.

You still risk getting a penalty fare if you get stopped on your
return journey (unless it's within two hours of your initial entry
where you'd probably only get charged 1GBP anyway when you exit from
the same station.)

There are some corner cases where this could work - I do Watford
Junction to London Euston every day. I'm pretty sure it only takes
1GBP to enter so if you're travelling during the peak hours you could
do a 5.50 journey for 4GBP. Of course you couldn't then continue onto
the underground so if you wanted to do a WJ to Zone 1 journey you'd
have to pay another 1.50 single rather than the extra 50p so a 6GBP
journey for 5GBP.

I don't know about entering at Euston for the return trip - I'd guess
you'd need 2GBP for this, being the single fare to South Hampstead so
you'd save 50p on the return trip. You might be able to do Z1 to
Watford Junction for the same 2GBP, saving you 1GBP.

Either way, the total savings are 2GBP per day in return for queuing
up twice per day to buy a new oyster. And I suspect the station staff
would eventually get to know you and start to get a bit suspicious.

On the legality, I suspect it's a matter of intent. If you eventually
intend to top up your card again, having a second card that allows you
to continue travelling when your first one goes overdrawn is ok. But
deliberately taking advantage of the overdraft facility without any
intention of ever repaying it would be theft.

Tim.