Yesterday I put up a video on YouTube talking about ways to be safe when viewing videos made to hypotize you. Quite a few videos are posted that have Dominance/Submission themese when they proclaim on their description to just be a little relaxation. (Honestly, this is because quite a few of them are using scripts written by someone else.) Most of the videos are pretty low quality, but just in case they work, it's important to be safe if you aren't looking to be someone's internet slave.
Some of the main tips I covered:
When you open a video page, pause the video and let it download fully in the background. While it's downloading, you can check out some of the other things I suggest, and once it's downloaded, you can scroll through it using the timeline to see exactly what text it is going to show you.
While you're waiting, check out the comment section. You might see that the video is wanting users to post their real name, or call the video uploader 'master', or other clues that it is trying to get you to do things it doesn't mention.
Also, check the video uploader's profile. A lot of times they'll be more up front there. While there you can also see the comments people have left on his or her profile, and see the other videos he or she has uploaded. These can all tell you whether it's a straightforward experience.
On the other hand, most of these videos with objectionable suggestions will only work if you really are looking for what it's truely offering, so there's not too much to worry about.
As I've said before, I have a website over at iHypnoU.com where I have a quick induction .mp3 that has no gimmicks or master/slave stuff in it. You'll also find a Tips page where if you are wanting a hypnosis video or mp3 to work, you'll find some info that will help.