header ROMPE_BADRECIPS To =~ /(uucp|majordomo|root)[EMAIL PROTECTED]/i
Bowie has answered your questions. A couple of comments on the regex above.
You should be using (?: instead of just ( to introduce the group. Without
the ?: it is a capturing group that will capture the text found. But you
aren't using the captured text, so this just considerably slows down the
regex processing.
You also should escape the dot in .com. What you have now will match any
character, not just a dot.
You should probably also make sure that there is a word break before the
username, so that you don't inadvertantly hit on mymajordomo or similar.
So you end up with:
To =~ /\b(?:uucp|majordomo|root)[EMAIL PROTECTED]/i
Loren