Well some people decided to find out and the results landed them some awards. See for yourself below:

Dictaphone Parcel from Lauri Warsta on Vimeo.

Animated short film, Royal College of Art, London, 2009
Dictaphone Parcel is an animation based on a sound recorded with a dictaphone travelling secretly inside a parcel. As the hidden recorder travels through the global mail system, from London to Helsinki, it captures the unexpected. We hear a mixture of abstract sounds, various types of transport and even discussions between the mail workers. The animation visualizes this journey by creating an imaginary documentary.

Dictaphone Parcel was awarded the Passion Pictures Prize in London, in February 2010.

See their website at http://www.cargocollective.com/lauriwarsta