What stops someone being hypnotised? (hypnotized)

Fear or the simple fact that they don't want to be hypnotised.

If someone does not allow themselves to be hypnotised, they won't be.

The fear of hypnosis usually means that someone is afraid that they will say or do something that they don't want to say or do, when of course no-one can be made to do anything that goes against any moral, ethical, spiritual or religious belief that they may have. They may be afraid that the hypnotist can exert some incredible power over them when in fact the above applies again. 

If I could “make” people do anything I wanted them to do, I would have already been employed by the British Armed Forces, been taught the relevant foreign language, and made a recording to be broadcast to the enemy as our troops entered the battle-zone.

*spoken in the relevant foreign language* “You will find that as you pick up your weapons, your legs turn to jelly, you put down your weapons, your elbows tuck neatly by your side and you all do the Birdy Dance, ready, da da da da da da da, da da da da da da da, da da da da, la la la la.”

Be happy,

Dave.