Unquoted "@" in From still in the wild?

Hello all,
I am fixing up the TMail mail library for Ruby.  As part of this, I am
incorporating the patches the Ruby on Rails guys have done to the library
for their implementation. But I am checking each one :)

There is a test case for an unquoted @ char in the from line.  Their
handling was to whack "@" into the ATOM_CHARS definition.  Per RFC 2822
3.2.4 this is not a valid character for the ATOM set.

The reason they put this in is to handle a bug in Apple Mail.app which was
not quoting the From field correctly if it contained a @ symbol.  This has
been fixed in subsequent revisions of Mail.app.  The problem is, that
putting @ into ATOM_CHARS obviously breaks other test cases in the TMail
library.

My question is 2 fold:

1) Removing @ is the obvious simple solution to return to the RFC2822 spec
as Apple have fixed Mail.app, but is this "bug" implemented elsewhere the
list members know of?  Should I spend the time to handle it in this edge
case in the library?  It looks like a bit of a hack to change the parser to
allow this and I don't want to go there if I don't _have_ to...

2) Is @ actually allowed in the description area of the From field (ie:
 From: mikel@me <[email protected]> ) from a revision to the RFC that I am
unaware of?

Thanks in advance.

Mikel