It doesn't, however it's less of a security related thing than a sorting filter. I haven't received a spoofed email in a while so the need is not as high.
Re: your mechanical turk idea, my email provider actually has something like that: https://documentation.cpanel.net/display/1144Docs/BoxTrapper - however there are so many use-cases where I think this would block some email I actually want (like my kid's school, my MD, ...) that I never dared doing it.
Re: your mechanical turk idea, my email provider actually has something like that: https://documentation.cpanel.net/display/1144Docs/BoxTrapper - however there are so many use-cases where I think this would block some email I actually want (like my kid's school, my MD, ...) that I never dared doing it.