If it's an email that is really hard to tell if it's spam or not, it's fine. But i'm getting regularly questions about mails that should be painfully obvious. Especially since those mails aren't unknown to the users in question. The usual crap about "expired password" or "check this totally legit onedrive website hosted on google drive, which i crafted in 2 minutes".

And since my boss doesn't want to adjust the spam filter, so that certain subject lines are filtered, i have to explain the same shit over and over again. Adding a button to make it easier to forward potentially infected emails would make it even more annoying. We're still using Office 2016 btw.