You might have thought this one was way too obvious to warrant actually saying, but no, apparently some people do need to be told:
"When sending a missive to a foreign diplomat, it’s best if you don’t use Babel Fish to handle the hassle of translation for you."
According to the How to Split an Atom blog, some Israeli journalists learned this lesson the hard way after using Babel Fish to translate a message to a Dutch foreign ministry. Wow. Read the full text of what they sent over at HtSaA, it even contains unintentional slurs against the guy's mother. Way to go!
Babel Fish is Not a Diplomatic Tool [How to Split an Atom]