Trust reference

[Susan Stewart]

Greetings,

I'm filing a bug for my IM client (Gajim) because it currently only
allows sending of encrypted and/or signed presence or messages to
contacts whose keys I trust ultimately (trust level 5).  The
documentation at http://gnupg.org/gph/en/manual.html#AEN346 appears out
of date, as it does not mention level 5 (ultimate trust) at all.

Is there some other reference that I could link in my bug to show that
ultimate trust should really be reserved for one's own keys, and that it
isn't wise to ultimately trust the key of every Alice, Bob, and Mallory
one would like to try encrypting a message to?

Thanks,

Susan