> if Google implemented my suggestion they could never be blacklisted
Google seems to have built their brand intentionally to be the opposite of what you're asking for though; and absolutely they could be blacklisted with a simple "GMAIL ADDRESSES NO LONGER ACCEPTED HERE".
>which already works but is security through obscurity.
I'm not sure which one you are saying is security through obscurity here... [email protected]... or the high entropy [email protected], both are obscure, but its a stretch of imagination to start labelling this a security issue.
Google seems to have built their brand intentionally to be the opposite of what you're asking for though; and absolutely they could be blacklisted with a simple "GMAIL ADDRESSES NO LONGER ACCEPTED HERE".
>which already works but is security through obscurity.
I'm not sure which one you are saying is security through obscurity here... [email protected]... or the high entropy [email protected], both are obscure, but its a stretch of imagination to start labelling this a security issue.