When you are hypnotized it's much like being in a meditative state, the only difference is that the therapist is the one helping you get to that relaxed state, much like a guided meditation. But at any state you can just open your eyes. Some states are deeper, but there is nothing a person will do or be controlled to that he or she would not do without being hypnotized.
Also, there is a big difference between stage hypnosis and clinical hypnosis. If you volunteer to go on stage and play along, you will be a perfect subject whether hypnotized or not.
In a clinical, therapeutic environment, we only work with positive and healthy changes and mindset. Who doesn't like that.