I think simply providing your stats. Age/build/race is enough. "Asking if" is allowing yourself to suffer the effect of racism over and over. YOU are a human being requesting time from a person who is supposed to be skilled in CUSTOMER SERVICE. You shouldn't just assume it's alright to be prejudiced. State your stats and fact and ask if they have time for you. If the answer is no, you can walk away assuming they are busy rather than humiliating yourself over and over being reminded that some people in this world are still assholes.