That's my interpretation, as well. The standard is for carriers, not mailboxes. As a carrier, (or someone sending an email) you should respect case, as well as

That's my interpretation, as well. The standard is for carriers, not mailboxes. As a carrier, (or someone sending an email) you should respect case, as well as respect all of the special characters, because the server is allowed full decision power over whether those things are meaningfully used.