On whose property? Did he get the owner's permission beforehand?
I guess you are also wondering where people collected all of those permissions to share media on Pirate Bay, too?
If you do, it's reasonable.
It's supposed to make the communication simpler, not to add more burden.
Hence, it was a poor analogy.
http://www.telegraph.co.uk/news/uknews/1549107/Banksys-30000...