Not Really Paranoid

I may not be the center of the universe, but there sure seem to be a lot of people that pay attention to me. And it's not just because I'm a somewhat tall American guy living in Shanghai. Or at least I don't think so, 'cause it seemed like lots of people payed similar attention to me in California.

That, and it's harder to notice I'm a tall American guy while we're driving along in a taxi. But apparently someone does. I thought they'd stopped looking out for me when we'd left America, but sadly, I was wrong.

In America, ambulances, police cars, cars with horns, bicycles with those bells, anything that's got at least two distinct tones seems to know exactly where I am. As I approach them, they play at one tone, the higher, and after I pass, they swap to the lower one. It can't be explained by physics and wavelengths, it can't be that my ears are simply having problems.

No, obviously people simply know where I am.

Of course, I suspect that the guy a few cars in front of me thinks he's being watched. For if the sound changes when I'm passed by, he's got to think it's because they notice him and just have delayed reactions.

It's not paranoia when the sound changes every time, right?