the reason it is difficult to find documented cases is because if the subject had post hypnotic amnesia which is very likely with a somnambulistic trance then as they were not aware what happened they would obviously not complain because they would have nothing to complain about.
to return to the telegraph article, it still illustrates my point.
She snapped out of the trance and realized what was happening. I mentioned before I have been hypnotized and a similar thing happened to me. I don't suppose you have been, so I will try to explain what its like. the very small part I remember is like a dream, in fact until I discovered what had happened I thought it was..
the reason it seems like a dream is because you are under the influence of the unconscious mind. now the word somnambulism has two meanings- the original from greek somn meaning sleep, and ambulare meaning walk, a person who walks and carries out activities in their sleep. because of the similarity to a person in a deep trance it took on that meaning also. but the diference is, when a person is put in a trance by another person then the operators suggestions become that persons inner voice and as its below the level of the conscious mind generally become accepted as the unconscious cannot reason in the same way. this is how stage hypnotists make subjects perform amusing acts. although there is some subconscious resistance, depending on the command and the subjects own personal beliefs.if the suggestion strongly violates the sujects moral code then he will very likely snap out of the trance, as their is some subconscious resistance, or, 'wake up' to put it another way, although, hypnosis is not sleep.this has happened to me. now, the subject will have no memory of what he was doing previously to the suggestion which made him snap out of the trance.
now, to return to the telegraph article, this woman 'woke up' and realised some of her clothing had been removed and the hypnotherapist was touching her, so it would not take her very long to realize he was trying to have sex with her, but she would have no memory of the events up to that point.
now if the hypnotherapist had not pushed his luck that far she could have been made to get dressed and put back to an innocent situation before being taken out of the trance by the hypnotherapist and she still could have been sexually assaulted and have no memory of it. or, if he had handled it differently had full sex with her. what about if he convinced her she was in love with him, for example.
I hope you will understand this explanation.