martini question
 

i've got what is probably a dumb question, but here goes. all the
recipes i've ever seen for martinis call for about 3 oz total of liquor.
yet when i see people order martinis in bars (i don't usually drink
cocktails myself), the cocktail glasses are usually filled to the top,
sometimes forcing the patron to take a careful sip before lifting the
glass.
i understand there is *some* dilution from stirring or shaking, but
certainly it can't be enough to fill the glass, can it?
are these people simply receiving a double or triple size drink? if so,
i never hear them specify "double" or "triple", and i don't recall them
paying two or three times the price of a normal drink.
if i were to make a martini for someone, and measured it carefully
according to the recipe, would they feel cheated if the glass weren't
full? do they come that way in proper bars?

-dan