Getting back into the Cage

A tacit urn
John Cage's famously silent piece of music (sic4'33" has been the subject of numerous Katposts (see eg here, most recently) and the IPKat had rather imagined that this little piece of copyright nonsense had run its course. Curiously, though, the concept of creative silence has just crossed his line of vision again thanks to a lead from London barrister Jonathan Turner (take a katpat, Jonathan!).  It appears that the Middle Temple Library is hosting an exhibition entitled Tacit Urns, this being a play on the words "tacit", meaning "silent", and "urns" as in "Grecian". The exhibition features the work of Sophie Arkette who explains:
"In Tacit Urns I have designed a series of glass urns (approximately 53 centimetres in height) that are receptacles for holding different types of silence. It can be thought of as similar to the idea of bottled water: as essentially a commodity. What happens to the value of silence if there is little of it around due to an ever increasing noisy environment? 
Would value be given to silence if it were captured and contained? In a future scenario, I propose that silence is bought and sold and valued relatively, according to the type of silence it represents. A rarefied silence of the kind found in a monastery might be considered more valuable than say the silent pauses that contribute towards a musical composition".
Where do John Cage and copyright silence come in?
John Cage
"The work Tacit Urns is as much about the way the urns come to contain the particular silence they do as the silent urns themselves. This means that the urns are required to undergo a period of infusion before they can be certified as containing that particular silence. An urn certified to contain Quaker silence is required to be present at a meeting of the brethren and a quiet urn is required to have been in an anechoic chamber. Copyright silence urn is to be infused by its being on stage during a performance of John Cage’s 4’33".