Let's say an honest answer: There may be a risk of IRL problems, and there is not a risk to get IRL problems because of hypnotists.
To keep it simple:
- All people are different. Some subjects can be very suggestible, some others aren't.
- On the contrary, all hypnotists aren't the same too: some know well the subject, and know then what they're doing, while some others are not that experienced, and doesn't know well how it works.
Now, the interesting part:
People that are correctly suggestible, may feel things, but for a short amount of time.
Other people that are very suggestible or want to feel X or Y suggestion will get those suggestions for a longer time, depending too on their deep levels.
As a hypnotist, let's program the subject then! And they want to get deeply relaxed once they hear a trigger; The hypnotist would implant it as "*****RELAX". (That trigger is not that common and basic, so adopt it in your sauce hopefully.)
Here comes the 2 kinds of hypnotists:
• The hypnotist will just use it raw. Meaning it can be a risk, depending of the suggestibility of someone. Imagine the worst. That person drives, and got triggered unexpectly. Deeply tranced, and highly risk an accident. Pretty risky, right? And the hypnotist wouldn't even be aware of it.
• The hypnotist know what he's doing, and will implant safeties aswell as your trigger. Meaning that he'd prevent any misuse or unexpected events. Example of safeties:
- Limiting it only with a person or a trusted person.
- Being activable only on a special place.
- Being alone or with someone you highly trust.
- The word would be activable with another trigger.
- Being activable with only an object you're wearing.
- Being activable only by SEEING the word, and not hearing it.
Much better, don't you think? And hopefully, it can be additionned.
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Also, keep in mind that a subject must not forget the main rule of hypnosis: TRUST, and self-awareness.
If you don't trust someone, you won't fully go into hypnosis. And if they say a suggestion you won't like, you'd wake up suddenly and make a kick on their nuts/middlebetween (or block them too :P ).
And self-awareness... Unless you want to be a complete slave/weak person with no more social life, you have to still be careful. And YOU have the power to break anything you find risky, temporarly or completely.
(Never forget that hypnosis is a deep relaxing state. Not a "you're not inside your mind anymore, your mine is mind, slave" (yes, it's normal)
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TL;DR: Everyone is different, and would react differently on hypnosis or how they would hypnotize people.
To start off: Always try your suggestibility level first, and be with people you trust a lot, to train you, and that he'd make a lot of safeties for you. And don't forget to tell them what you want to feel/experience! The more you know each others, the better!
(also: On IRC, hibikini has its program updated a little to text-hypnotize people privately, with easy and basic suggestions. But it's still under deep tests, and might not always work for now :/ )