I went to one of those hypnotist shows one time in college. It was free, about an hour long, and I wasn't doing anything else at the time, so why not? Any how, I was surprised that about 10% of the crowd fell into a trance and did what they guy told them to do. A few people I didn't know or recognize at all (plants?), but I did know several who went right along with it. I didn't get it, didn't have to resist anything, could tell that going along with it wasn't going to work on me.

My recollections of it are vague, but I remember asking one person about the experience. Based on what he said, the best way to explain it is like sleep walking.

In conclusion, I suspect 10%-20% of the population are like that - open to suggestion, and will do what they are told to do without really knowing that they are doing it.