It is an unsupported claim of TrueCrypt, you should not trust it.
Their website and all of their documentation would lead one to believe otherwise. I have experiemented with the feature personally and have yet to see anything (other then your suggestion) that suggests that it shouldn't be used. I don't suppose you have any supporting information you'd like to share?
That's not the point. They have to prove that their claim is true. Until they haven't done that, you should not trust it. That's the only way to do security.