Steve and Mark - you both have reasonablee positions, but there is a
If someone wants to send an arbitrary structured message and use
privacy-enhancement, then the user-agent MUST give the user the ability
to specify whether each component or the entire structure is to be
privacy-enhanced. Users who opt for total privacy should be aware that
they may be sending messages that can not be processed by correspondents
who use split-UA architectures.
Hence, a UA doing both PEM&MIME must, Must, MUST provide the option for
full- and. component- privacy.