C'est d'ailleurs indiqué dans la note :

"Notes:

This scheme is not infallible. Although signing the declaration makes it impossible for a third party to produce arbitrary declarations, it does not prevent them from using force to coerce rsync.net to produce false declarations. The news clip in the signed message serves to demonstrate that that update could not have been created prior to that date. It shows that a series of these updates were not created in advance and posted on this page."