On 26-Feb-12 12:52, Roland Perry wrote:
In message , at 18:32:17 on Sun, 26 Feb
2012, Adam H. Kerman remarked:
What do you do ... at a restaurant, when the tip amount to be charged
is not known until later,

In a UK restaurant you have to add the tip to the bill before contacting
the card company. That's not so very different from my experience in the
USA where they give you the bill, with an empty field for the tip, which
you hand to the waiter *filled in* (along with your card).

The only* way I've ever seen it in the US is this:

1. The waiter presents an itemized bill _without_ a tip line.
2. You either give him cash (including tip) or a card.
3. The waiter swipes the card in the register, which authorizes the card
for the bill plus an estimated tip.
4. The waiter returns with the card and two slips showing the subtotal,
empty tip line, and empty total line.
5. You fill in the tip and total on the "merchant copy" slip, sign the
slip and hand it back to the waiter. You can leave now. (You should
also fill the tip and total on the "customer copy" slip, for your own
records.)
6. The waiter enters the tip into the register, which updates the credit
card transaction with the correct total for when it's posted later.


(* Aside from "large" parties where a fixed gratuity may be added to the
bill automatically, in which case the transaction proceeds as it does
with normal merchants.)

S

--
Stephen Sprunk "God does not play dice." --Albert Einstein
CCIE #3723 "God is an inveterate gambler, and He throws the
K5SSS dice at every possible opportunity." --Stephen Hawking