Ron Natalie wrote:

Morgans wrote:
saction

amount known yet just to make sure there will be enough funds available.
Examples are pay-at-the-gas-pump transactions (usually $50 is

preauthorized

before you start pumping),

Actually, that's WRONG. What they usually do is put through a $1
preauthorization. The $50 limit they put on the pumping is a number
that the point of sale determines is the max they will do based on that
$1 preauth.

I'm familiar with pump POS systems that preauthorize $50. YMMV.

If the customer spends more than is preauthorized the merchant is not
guaranteed to get those funds. However I'm not surprised that some gas
stations would not be willing to take that risk since they readily accept
the risk of not requiring a signature, let alone not checking the signature.