Anonymize email through the + feature?

Email has the feature where one can suffix “+” and a string to create an alias. One can have a main and sub account, apply aliases to the sub account like sub+netflix@example.com and then forward the emails sent to this address to the main account, therefore never exposing the main account email.

The problem is, since this is an email feature, site admins that aim to send spam can filter out all strings after “+” and then send the spam …

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