Just wanted to share a bit of my own experience with hypnosis and hypnotic recordings.
I am prone to migraine and even on preventative meds I still suffer from them occasionally. I am hyper-sensitive with many of my senses and I have triggers that I avoid - movies with flashing lights, nightclubs where there are a lot of strobe lights, etc.
Unfortunately I have found that any hypnosis recordings that use binaural beats will trigger a migraine for me every time.
Please note that this may not happen for everyone who has the tendency toward migraine, however it would be a good idea if you wish to try using a binaural recording to test it first on a day where you do not have many responsibilities and have your meds handy in case you do have a reaction.
Fortunately I have not found subiminals to affect me in this way and I can use many other types of recordings and videos with much pleasure and relaxation response.