Ask HN: Proposed HNDM Design

Suppose that HN user Foo wishes to DM user Bar. HN knows their real email addresses, so Foo emails Bar@hndm.com, and HNDM auto-forwards this to Bar's real email address. If Foo wants a response from Bar, Foo needs to tell Bar their (Foo's) real email address, and Bar can email them directly. The only accepted/understood direct reply to one of these forwards is "block", which will forever block Foo from sending to Bar. If Foo gets three blocks, they're disallowed from sending HNDMs until the they are under three blocks, which clear at one block/week.