[IIsi50MHz]

The optional dots would seem to be irrelevant. You seem to be asking that all email sent to your address, but not intended for you, to be bounced. An email address can only be validated (as in "Is this an email address?") by trying to send mail to it. Assuming the mail is deliverable, there is literally no way for the sender or any mail server involved to know whether the address on the message has anything to do with any person who has access to the contents of that mailbox.

The only possible way that I know of to provide feedback is to send a reply to the sending address. Perhaps you're asking for an addition to the email system so that a recipient can "click a button" to generate at the protocol level a response from your mail server like "errNum% - Wrong recipient. Undeliverable as addressed."?

[richardw]

No, I want all mail that doesn’t use the email address I chose, which is “fred.flintstone@gmail” to be blocked as it would be on any other mail platform. I want gmail to act like any other mail provider, no dot innovation because I don’t want it. I’ve had this address since 2005. That’s a long time to learn about the benefits and costs.

Rule: for any email address variant that is not what the user selected, reply with “550 no such user here”.

Instant reduction in both spam and mistyped emails. Instant feedback to sender.