If you want to tell your hypnotist/hypnotherapist/therapist/radio/tv personality your innermost secrets then that’s really up to you. If you do tell them something then it is because you want to and not because the Hypnotist forced you too.
Under hypnosis you’re still fully aware of what’s going on and you, as the client are in control during the whole session and it will be your choice what to say and what not to say during a session.
When running a hypnotherapy practice there were a number of occasions where a client would talk incessantly dropping a huge number of ‘secrets’ to me most of which were pretty innocuous and were often followed with a comment such as ‘I didn’t shock you’ at the end of the session. On these occasions I found either the client just wanted to talk to someone and saw that I was a Therapist and basically did a brain dump of their problems or they were testing me to see if I could be shocked or would talk about them. Unless what they revealed were illegal actives (which I had a duty to report) I pretty much ignored them.