It's the first time I'm hearing of it, for whatever that's worth. Usually the problem seems to be with men taking it as a sign of romantic interest.
Either way, I just try to smile or say some trivial pleasantry for her efforts and then go back to doing whatever it was I was doing. I don't take that kind of attitude as more than something she's doing because she likes it that way. Then again, I don't tend to take much interest in people's affairs to begin with, so a grain of salt may be advised