Seeing double(s)

I have an eye for doppelgangers. I have found the face of a good friend in Sweden and spied a colleague, twenty years in the future, riding the 6 train downtown. My iPhone is my favorite accomplice in secretly documenting the matches that my eye has made, since it's oh-so innocuous to, headphones in ears, lift the phone ever so slightly to snap a picture. Is it stalking if it's only once?