I respect your thoughts, and understand your concerns about the files here, but I think you have to allow people to make their own decisions and be responsible enough to accept the consequences. When anyone signs up to this website and messageboard, they certify that they're at least eighteen years old and (depending on nationality) therefore over the age of consent. Everyone here is an adult and should be treated as such.
Self-hypnosis is a tool; different people can and are going to use it in different ways. Yes, it can be dangerous for some people, just as a knife is dangerous in the wrong hands, which is why a lot of shops won't sell them to minors. But the misuse of a tool is no more the fault of this website than of the retailer; you can't put everything that's slightly dangerous under control just because some people harm themselves or others with them.
Like a number of people here, I'm involved in the BDSM community, and the near-universal approach of 'safe, sane and consensual' applies just as much here as it does there. More so, in fact; in BDSM the dominant's control is over your body whereas the hypnotist's control can be over both your body and your mind. So apply those rules; don't do it unless you consider the effects of the file safe, you consider it sane and consent to its affects on you by not listening unless you fully agree to allow whatever the file says to affect you.