In this case there actually is a benefit. I've seen issues where people weren't able to communicate with customers because someone's running a mail server that

In this case there actually is a benefit. I've seen issues where people weren't able to communicate with customers because someone's running a mail server that rejects email based on the RFC-Clueless RBL or its predecessor, RFC-Ignorant[0]. I've never in history seen postmaster@domain every receive anything but spam, and I have seen it receive so much spam that I would never identify a legitimate email amongst the screens full of junk if one ever did arrive. [0] http://rfc-clueless.org/pages/faq http://rfc-clueless.org/pages/faq