draft-lilly-from-optional-01.txt makes the From: field optional. According to
4.2. RFC 822 section 4.4.2, the Sender field is optional as well.
I suggest that your draft amends Section 3.6.2 of RFC 2822 and 4.2. RFC 822
section 4.4.2 as follows:
If the from field is omitted then the sender field, containing the field
name "Sender" and a single mailbox specification, MUST appear in the message.
If the From field is omitted, a Sender field MUST be supplied.
The above changes do not affect the anonymity of the author or authors
while allowing domain-based email authentication if the sender implements it.
Regards,
-sm