We went to Lucerne on Friday (it was another Swiss holiday! Yeah!). While waiting for food at a little deli a man came up next to us and handed the woman behind the counter his purchases. The total came to about 7CHF. He pulled out his credit card.
Note, up until this point, the man had not opened his mouth. He was a generic looking white guy.
The woman, who had spoken to me in German, said to him, in perfect English: "Ten Franc minimum on credit card purchases."
I guess it's only the Americans (or Canadians, Brits, Australians?) who would think to buy a small purchase on a credit card.