Flying home from Frankfurt yesterday via Chicago, as usual I randomly selected a shortish looking line in the immigration and customs hall. When it was my turn, the agent behind the counter saw the "business" box checked on my form and asked who I work for, which is pretty standard. He then asked me what I do for HP, but before I could answer, he said "No, wait. You've been through here before. I recognize your passport."
I managed to retain my composure just enough to agree that he certainly could have seen my passport before. He smiled, stamped my form, and waved me through.
My wife wonders why I was so surprised.