>> The 'seqno'  is here only because  RFC822 does not force  mailers to keep
>> RFC822 fields in the order in which they were mentioned. Thus a mailer on
>> the path might mess the header into:
>
>It seems to be a rather weak standard as it stands.  It's been done over
>before.  Anyone for another time?
 
no, all we have to do is register some additonal defined headers as defined
in the standard.  Lets not have the kind of fights that go on for
new versions of standards.