Interesting research here.
They say: “An accelerometer fingerprint can serve as an electronic
cookie, empowering an adversary to consolidate data per user, and track
them over space and time. Alarmingly, such a cookie is hard to erase,
unless the accelerometer wears out to the degree that its fingerprint
becomes inconsistent. We have not noticed any evidence of this in the
nine months of experimentation with 107 accelerometers.”
It would be interesting to know how accurate this really is once you start getting into 1000's and 100,000's of devices. While I can see where you could determine general info about what device and accelerometer is it in, using it to track and individual user may be a bit more problematic. With that said, I haven't read the 16 page right up yet, just the quick news article and with that I'll admit I scanned it.
Interesting approach and cool way to do it!