G'day silver fans and welcome back to Woddonnee!
Perth Mint holds physical silver for every UN-allocated ounce held by certificate holders. It does not lease out silver either. Go here to read their full statement on the certificate backing.
http://www.perthmint.com.au/gc/depository/depository_layout.asp?url=5
I hold silver certificates for unallocated metal and I am quite comfortable about it!
Cheers
