Can anyone be hypnotised?

The answer to this is mostly yes. You don't need to be in a deep trance, but it certainly helps if you are willing. If you go out of your way to resist it, you are wasting everyone's time and your money. Focus on relaxing, and let your imagination experience everything through your senses: touch, sight, hearing, feeling, and even taste! 

Sometimes, people on extreme ends of the autistic spectrum may not be the best candidates for hypnosis.  Similarly, people under the influence of either drugs or alcohol are futile candidates for hypnosis.