I wonder if using an address @nationalgeographic.com (e.g. support) might illuminate to them how foolish this is...

Yeah, I tend to do support@[target domain] if a site gets too annoying with their popups.

Don't make up domain names for this. Always use example.com

Why it has to be meaningful words? Why not qwqeeq@qqekqe.com? :-)

or <vulgar>@<vulgar.tld>

Awesome trick. Thanks!