I am not that familiar with the Emailer, but I experimented a bit with it and I find it a bit worrisome that I can send a mail from one mail adress (not necessarily mine) to another mail adress. I tested using my colleague's mail adress to send a mail to my own mail adress and I don't need to authenticate that I am the colleague.
You can choose yourself to have the sender's authentication on, but I would prefer that it's always required so you will be sure that the person who sents the mail is indeed the sender and not someone else.
