I think you can generally consider that people will do whatever comes naturally to them when given an 'excuse' like hypnotism to absolve responsibility for their actions. You can look at this from the viewpoint of social role theory that considers that we all take on particular roles or personas depending on the situation we are in and what we think is expected of us (for example you act differently around your friends than you would around your parents, or possibly your workmates) The 'role' of the hypnotised subject is dependant on the suggestions and vibe of the performance so people act accordingly.
Another thing to consider is that we all have very selective attention and will tend to fill in gaps and jump to conclusions when dealing with sensory data. This can be manipulated to make people think they have come up with ideas or to help them jump to the conclusions you want. For some very good work along these lines check out Derren Brown on youtube.
Basically mass hypnosis or 'mind control' is possible but difficult and will only ever work within the bounds of what the subjects are comfortable with. Of course over time and with repeated and consistent effort you could probably move a groups 'zone of comfort' towards whatever you wanted to achieve
