As an event manager you can sometimes experience resistance from people who don't seem to want to participate in an event. This can take various forms. Often with younger participants they act as though they are 'too cool' to take part in something where the stated objective is to relax and have fun. Another version of this, often with higher level executives, is an apparent preference for doing something on their smartphone rather than engaging in the activity.
The motivation behind both of these behaviours is often fear; a concern that they will need to do something that will make them feel silly or uncomfortable. This is particularly the case when the controversial subject of role play comes up. For example, when a group is told that the activity is a Murder Mystery and this is a surprise many will recoil from it because they don't yet know the level at which they will be asked to participate.
Experienced event managers understand that everyone is different and brings their own set of concerns to an event. An inexperienced event manager will try to bulldoze through situations, or not notice that they exist, and that can make matters worse.
In a briefing an event manager can specifically target people by aiming information at them, in a subtle way. So, when signs of resistance are evident in body language - for example crossed arms and a set jaw - you can look at that person when you make a point such as; 'No-one will be forced to do anything that they don't feel comfortable doing'. This builds trust and reassures that person about the coming event.
This is one of the many reasons why having an experienced event manager who understands people is beneficial. To get the most out of a group you need to be able to read them and make the effort to treat each member of a group as an individual.
If, after the event, people say; 'I didn't think that I'd enjoy that but I really did' then it should be a huge compliment to the event manager and his team. It is a sign of experience in action.