How weird. Why would he have to explain himself even if he did pay with credit card everyday. He paid with cash so what. Millions have had to cancel their credit cards because a hacker tried to use it. Heck I have had to cancel a bank card three times over the last 3 years because of it.
Well, you get to be friendly with the people in a place, they know your habits, and when you do something different you may very well get into talking about it.