"user(_at_)domain(_dot_)com <user(_at_)domain(_dot_)com>" is not legal under
RFC 2822. It is
must not generate under either current (section 3) or obsolete (section
4) grammar.
true, it's illegal to have an '@' in a phrase unless its quoted.
it was illegal in RFC 822 also, which means it's been illegal for 20
years or so. an '@' can't appear in an atom.
perhaps even worse, it's redundant. why say
user(_at_)domain(_dot_)com <user(_at_)domain(_dot_)com>
or even
"user(_at_)domain(_dot_)com" <user(_at_)domain(_dot_)com>
when simply
user(_at_)domain(_dot_)com
will do?
a phrase containing another copy of the address conveys no additional
information, it just wastes bandwidth and invites stupid mail handling tools
to play with it.
Keith