Yeah, it seems clients are lagging behind with this. Visually marking emails which are from new domains or addresses is a nice idea. The From header should be

Yeah, it seems clients are lagging behind with this. Visually marking emails which are from new domains or addresses is a nice idea. The From header should be much more prominent too. For example, perhaps a user should be presented with the email address in large text and explicitly asked to “trust” it before viewing emails for that address (similar to SSH). People would probably get fatigued of that and click through though, of course (similar to SSH... although it’s much easier to quickly check whether an email address is as expected compared to a SSH fingerprint).