Is there ever justification for 'red flagging' emails?

I have to admit, when I get an email with a red flag stating it is 'important', it raises antibodies with me. I strongly suspect the person at the other end has a dysfunctional relationship with email and doesn't fully understand how communication works. Of course, some of this is just workplace norms, and people get subjected to this in their organisation or institution, and the only way to get…