On Feb 26, 9:49*pm, Roland Perry wrote:

In message , at 14:30:31 on Sun, 26 Feb
2012, Stephen Sprunk remarked:

The pumps had a sign suggesting that Electron card users put in at least
GBP 20 worth or else a larger amount of the balance on the associated
account would remain earmarked for a few days.

Sounds like they're authorizing the card for GBP 20, as discussed
elsewhere in this thread.

Not authorising, because that's "Electron" is a debit card on an account
which doesn't allow an overdraft. They will be deducting the £20
straight away, and allowing only up to £20 of fuel. If you buy less, it
sometimes takes a while for them to credit it you with the balance.

That would be pre-payment - and I don't think that happens, does it?
If one presents an Electron card which is then pre-authorised online
for a sum of up to £99 (or whatever), there's no need to actually get
pre-payment - because the pre-authorisation means that the card holder
is known to be good for payment.

Rather, this sounds to me like some sort of artefact that occurs when
an Electron card is pre-authorised for £99 (or whatever) but only a
small fuel purchase is actually made, then the pre-authorisation hold
on those funds takes longer to clear than if a more substantial
purchase of £20 plus was made.