There are no stationary objects in the Universe

[Nerb]

Those researchers recorded the vibrations from a potato chip bag, one made of foil, and were able to isolate the vibrations still vibrating from the earlier conversation. A bit alarming, as well as exciting.

I was going to say that to avoid having an important conversation detected from the residual vibrations being measured it could be impossible to read if music was played at the same time, BUT, if the researchers (spies) were clever they could also isolate the music once it was recognised and then read the conversation anyway.

Perhaps white noise is the answer to remaining undetectable against these kind of technologies.