I'm not sure if I have "the look". I was in Singapore last year for work and eating dinner at the airport with a group where I was the only "asian-looking" one. All the staff seemed to be speaking Cantonese to each other. One of the waiters walked directly to me and asked me a question in Mandarin. I had wondered why he assumed that I spoke Mandarin. I had been speaking English to my co-workers the entire time. I assumed because Mandarin is more prevalent over there.