I have had an opposite situation happen many years ago.

I was hired by another franchisee of a popular fast food chain and placed in a store in South Beach. After working a few hours in the back of the store, getting to know the employees, I walked to the front registers to assist the lines that developed as a convention or meeting being held had a break and we filled up quickly. While assisting, I had a customer approach me and started blurting out in rapid Spanish. I didn't understand much as it had been at least 2 years since I had really heard Spanish and took my classes in High School. When she finished her speaking, I said "Sorry, I don't speak Spanish." She then said in perfect English, "What!!!!? You look Cuban,!!" I am as Gringo as a Gringo could be.