A stranger walks into a bar and puts a pound coin on the counter and asks for half a pint of bitter. The barmaid asks him whether he would like Guinness or Worthington. The stranger asks for Guinness. Another complete stranger comes into the bar, puts a pound on the counter and also asks for half a pint of bitter. The barmaid immediately pulls half a pint of Guinness. How did she know what the second man, who was completely unknown to her, wanted?

(think in a crooked way for this one)