The principle behind show hypnosis and clinical hypnosis must be the same but t don't use it to make us do the chicken.. Anyway, we do what we wanna do, even "under" hypnosis, we're still in control of what we do, think and say. We can step out anytime we want; the hypnotherapist doesn't control us at all. There are many states you can be.. I guess I'm somewhere between light and moderate when we use hypnosis; I hear most of what t says and remember basically everything but there a state of relaxation and calm that is so interesting...
Everybody has his own perceptions and beliefs around it and it's fine this way but for it to be useful, you need to "believe" in it, trust your t and be ready to let go if I can say that this way... But I'm not sure for memory recovery as well. Like 3rdtimesthecharm says, what you can remember under hypnosis is not necessarely fact; it can easily be a construction of many thing or other said, a false memory