I've worked at a face recognition startup for 5 years now. I've already solved this guy's problem. You have the correct answer. My response is slightly modified

I've worked at a face recognition startup for 5 years now. I've already solved this guy's problem. You have the correct answer. My response is slightly modified in that I open with "I work at a software startup... we do face recognition". And if they ask how it works, I say "We don't teach computers how to recognize faces, we teach computers how to learn how to recognize faces" and most people tend to light up (and/or have their mind blown). If you mention "startup", "face recognition", and "teaching computers how to learn", virtually everyone has something they want to talk about.