Which ever dumbass that said "honesty is the best policy" is a fucking liar.
I read enough news articles to know this, if you want to preserve your freedom (that is, the very little remaining freedom that you still have under this ultra-capitalistic world), you have to lie, otherwise you will end up in a place wose than prison.
Therapy is usually voluntary, and the people going are going for a reason and that's usually to better themselves or help themselves in some way. So lying is just a massive waste of money and time.