A very large loophole exists in the spam filtering, whereby a user on google mail for example can send an email to you via "drive-shares-dm-noreply@google.com" and that email arrives with their own address as the "reply to" address ... BUT IF I were to say that email is junk, it is going to label the google . com email as junk, and I have no ability to isolate the reply-to address as junk, which is the only one of the two I want to label as junk ... so this needs fixing, and it makes me think that it would be a fair bet to think if this loophole exists, there is probably something similar going on with group emails and cc/bcc fields ... something to look into for sure