[unnouinceput]

Yes. Also search WW2 war stories about radio operators, this technique dates back since then. US Pacific operators always knew which Japanese radio operator was transmitting Morse codes by listening to their typing patterns. And if a human was able to do it, imagine the accuracy of computers in this regard.

[ridgeguy]

I was a ham radio operator for several years. It was easy to ID my frequent contacts by their morse code transmission patterns, and they me. An operator's pattern was called their "fist".