This is an interesting topic. It seems to me that it could be that we are more responsive to hypnotism in a group. For instance rallies of any sort will allow us to get caught up in the moment (even without the 'funny' cigarettes etc). I'm thinking, for eg, of religious rallies, Hitler's brilliant manipulation at his rallies and of course good old Rock concerts. People are in a highly emotional state at these events, and even in small groups of people can behave in ways they would not as an individual.

Though is this hypnotism? Or is this 'group consciousness' something that a skilled hypnotist may be able to exploit in an individual. Certainly there have been many religious leaders, politicians, military commanders and rock singers who do just that. I mean- manipulate peoples' emotions for their own advantage.