Cameras basically read their sensors one row of pixels at a time. By measuring the distortion of each row, they can detect vibrations higher than the camera's frame rate.
So having a rolling shutter is good for this specific application because it trades off resolution (most of which is redundant or insignificant information) for sampling rate.
- Actually, doing a quick calculation shows that at 1khz a 1/2 wavelength is just 17cm. I wonder how precise spatial scene/source information has to be to allow this diversity to contribute significantly to the sampling. If you had a planar source and precisely spaced two objects it shouldn't be too hard to increase spectral resolution. The complementary possibilities are also be interesting -- with precisely laid out N objects and a good spectral resolution for each afforded by the shutter you could perhaps resolve the sound into N distinct sources, allowing to determine the origin of the sound; with precisely known source locations you may be able to extract some object location information.