Apparently, I Exude Physicistiness

So I'm going to be observing in Arizona for about the next week. This evening, I was waiting for the other graduate student to get off of the plane in Tucson, I was just standing next to my luggage. A Japanese man, about 60 years old, comes up to me (as he's leaving the jetway) and asks (I kid you not): "*mumble, mumble,* are you a physicist?" Me: "*stammer, stammer,* yes." He asked what I was doing here, and I said observing at MDM, and he was like, "oh, okay," and went away. I didn't realize the weirdness of this story until after he'd left (I'd been asleep on the plane so I was not exactly "awake" yet) ... but I don't think there was anything about me that screamed, "I am a physicist!" I checked, and I wasn't wearing a physics shirt or even anything particularly nerdy (is a Hawaiian shirt, black slacks, and black loafers that unusual?). The other graduate student postulated that perhaps he had been in earshot of our conversation at the beginning of the flight over which temperature scale is superior (which included calculating the average body temparture in Celsius); apparently the guy across the aisle from me had been shooting us weird looks for the duration of this discussion. But does a discussion of temperature scales really give it away that I'm a physicist?