These two statements conflict:
It is harder to fake the URI from which a feed is actually read.
as identified in a link element (with rel="self") and the atom:id of the entry.
rel=self doesn't contain where the feed came from, it contains where the feed claims it came from, and since it has no constraints on uniqueness or persistence, but is just as easy to spoof as id, it's an even worse choice.
A better thing to do would be to add a missing feature to the source element: Where the feed actually came from. I'd suggest it being a uri/href/src attribute on the source element itself, since it describes the sourcing of the feed. Adding an element within <source> would imply the new element was part of the original feed.
Then we need a new Pace that uses the original URI.
(I'm also starting to think that feed ids are a bit of a waste of space, but anyway...)
Graham
