Search the blog or my web site for my very negative comments on that. I don’t think all technical approaches fail. If you “take one for the team” and accept and then discard the spam, it does not direct the spam at your neighbour as directly as tempfailing.

Tempfailing deserves particulary scrutiny because the more people do it, the worse it actually will work, unlike some other technical measures, such as rate-limiting, which get better the more people do them.