@eletrotupi
I get email from banks/brokers that arrive as a multipart MIME msg, & the "text/plain" part states nothing more than "you need to update your mail program for better security". The "text/html" part actually conveys a useful msg. So although my text MUA is smart enough to render HTML in text form, it also favors the "text/plain" part if it's there, thus hiding the msg.

We should start sending emails with an HTML part that says "turn off HTML to read this msg".