Figuring out if mail is SPAM or what words are offensive is difficult, even more difficult is the problem of avoiding false positives. Most of this I knew, but I never spent to much time on the details. While following an internal discussion I learned that there is actually a name for some of these problems - The Scunthorpe Problem. A good mix of of the problems can be found on this Wikipedia link.
btw - now I'm wondering if mentioning the Scunthrope problem will put this enrty on some blacklists, I hope people are learning from others experience (hahaha - fat chance)