some requests

I would like to request one thing to openpgp-mime-02.txt.

Section 3 says:

   Additionally, if body parts to be signed contain trailing whitespace,
   or lines beginning with the five characters "From ", implementations
   SHOULD use either Quoted-Printable or Base64 to protect these body
   parts against corruption by transport or delivery agents.  Applying
   this rule also ensures that trailing whitespace in the data encoded
   cannot be modified without invalidating the signature.
      
I feel that "SHOULD" is too strong. I have two reasons.

(1) In the ISO-2022 environment (including Korean and Japanese), for
    long historical reasons, applying CTE: breaks inter-operability
    between MUAs. Even base64, which is considered more suitable to
    ISO-2022-{JP,KR} than quoted-printable, should not be applied to
    ISO-2022-{JP,KR} anyway. So, SHOULD is too strong for this kind
    of environment.

(2) This rule implies that MUAs SHOULD search "From " pattern from
    text in a deeply nested multipart. This is too tough for many
    MUAs.

--Kazu