A list of Google Instant's banned words and phrases
It shouldn't really come as a surprise that Google has a blacklist for Google Instant -- after all, the vast majority of searchers won't be looking for anything on the list -- but it does surprise me that there's no way to turn off the blacklisting. Even with SafeSearch Filtering turned off, the blacklist is still triggered.
It wouldn't be hard for Google to provide real Google Instant for those that want it. Perhaps that config option is coming -- or perhaps this is one of Google's larger steps into controlling our Web-surfing experience.