Interesting, i didn't think those ware allowed in emails.
I tested them out with gmail, but they mostly fail, but not all in the same way. The SMTP server outright refuses to accept all of them, but gives slightly different errors for some. The Gmail web interface also refuses most of them ( Like the "", "..", (comment) etc...) but again with varying errors. For some it complains upon clicking send and doesn't even try to send it, for some it does attempt to send it but reports back that an error has occurred during sending but does not say what kind of error. The one that did send successfully was "john.smith"@gmail.com but it never arrived in the inbox, nor did i get it returned to sender.
So apparently no gmail does not like any of these weird email formats.