On Sun, 26 Feb 2012 18:32:17 +0000 (UTC), "Adam H. Kerman"
wrote:
Uh, always? What do you do at a fuel station which requires a credit
card before dispensing fuel, or at a restaurant, when the tip amount
to be charged is not known until later

In the latter case, you usually enter the tip into the machine before
giving your PIN.

Neil

--
Neil Williams, Milton Keynes, UK