In the official Truecrypt website, "plausible deniability" is one of its selling points.
Rather, this article argues something different, which is that in some (extreme) circumstances, plausible deniability won't help you much (though it's still optimal in that it's a "strictly dominant" strategy) . To which i would say "no duh".
I get that this is a big deal though, from a "is truecrypt" usable standpoint though...I just think that people should base their security procedures on more practical measures.