Yes, that's true with any self-report instrument—they're only as good as the honesty of your responses. This is more of an issue where people are trying to achieve something other than insight with their responses (i.e. taking a personality test to get a job). Of course, sometimes people do lie to themselves as well!

Since our tests are really designed for personal exploration, we don't try to control for whether people are being truthful. As with so many things in life, you get out what you put in!