One summer I worked as a grocery store clerk. We ID'd everybody. I go with blind adherence for two reasons: first, the company would fire me without hesitation if I didn't and second, i would be fined and/or arrested(me, not just the store) if a cop saw me since where I live the law says 100% ID check. Some cranky old man is not worth either one happening to me. Actually, most of my friends at the time wouldn't have been worth it either.