Math behind Bump(ing)?

Question

I was randomly looking at the FAQ for bu.mp (http://bu.mp/faq), and this part caught my eye:

Q: No way. What if somebody else bumps at the same time?

Way. We use various techniques to limit the pool of potential matches, including location information and characteristics of the bump event. If you are bumping in a particularly dense area (ex, at a conference), and we cannot resolve a unique match after a single bump, we'll just ask you to bump again. Our CTO has a PhD in Quantum Mechanics and can show the math behind that, but we suggest downloading Bump and trying it yourself!

Is there really any reason why there might be some non-trivial math behind bumping, or is the "Our CTO has a PhD in Quantum Mechanics and can show the math behind that" probably just a bit tongue-in-cheek? [I'm having a hard time imagining why something more complicated than looking at the location+time would be necessary, but maybe I'm just underestimating the problem or the kinds of data an iPhone could collect from a bump (e.g., some kind of tremor waveform?).]

Answer 1

I sincerely doubt there's any overly complex math involved. It just matches "bumps" that occur within a very short span of time in a particular area.

If there is more than one match within that particular timespan AND within that area it probably asks you to bump again.