Of course fully translated content is optimal, but If a tool like Google Translate is to be used I would use a workflow that alerts the user that translation will be rudimentary and should only be used to get the "jist" of the content. Also, any specific questions should be directed at someone who can help them from that point.
Technically, you could pass the referring URL into a form, present those messages, and then have a "Translate Now" button. The user would be prepared for what he or she would be receiving, have contact information for someone to call or email questions, and get some semblance of content.
I think this is a better approach than "It's not perfect, so don't even try".
Gotta agree with Matt here. If content-in-another-language is one of your goals (and, that's a smart goal to have; take it from a Spanish/English speaker!), have someone do it well. Don't rely on software.
The last thing you want to do is offend/alienate your intended audience with content that shows that you don't really care if they understand you.