killfile.sieve

require "vacation";
if anyof (address "From" "bunghole@company.org")
{
  vacation :days 1 :addresses ["me@company.org"]
"This mail will not be read by me, it has been expunged to /dev/null instead.

Apparently, I put your mail address into my killfile.
  
You sent me an unusual amount of annoying, unsolicited, and undesirable mail in the past.
This is not an error, I register each killfile entry manually and very carefully.
  
Go away.";
  discard;
  stop;
}