Part-way through a trip from D.C. to Boston I ordered a sandwich and a can of ginger ale on the train. I did not specify a brand of ginger ale, but the clerk to

Part-way through a trip from D.C. to Boston I ordered a sandwich and a can of ginger ale on the train. I did not specify a brand of ginger ale, but the clerk told me that they were out of Schweppes, and that he didn't want to bother charging me for Canada Dry, so he gave it to me for free.