The problem is that it is trivial to delete anything after (and including) the + from an e-mail address. I've had this happen when trying to use this approach.

The problem is that it is trivial to delete anything after (and including) the + from an e-mail address. I've had this happen when trying to use this approach. What I do instead is this: I have a subdomain of my regular domain, say "me.example.com." That subdomain is a catch-all; anything sent to it goes to my regular account at "example.com," though I have a Sieve rule to filter those messages to their own folder. Companies and so forth get addresses like companyname@me.example.com or, if I'm giving one in person, myname3@me.example.com so it doesn't seem odd. At that point, they can't tell the difference between that being a tagged address or not, so the entire address has to be sent untouched. I can then do whatever I like with it, namely trashing the message in a rule. Using a subdomain is preferable for keeping the generic spam down since those aren't as easily discovered.