0 a person who watches an activity, especially a sports event, without taking part:
1 a person who watches an activity, esp. a public event, without taking part:
The space described above had a distinct, 'sacred' quality, clearly demarcating the performers from the spectators.
This certainly was the most effective act of transgression which made amorphous the distinction between the performers and spectators!
What is most significant is that there were only a few hundred spectators, only around double the number of the performers.
The spectators standing on the ground below were looking up at performers walking along a vertical surface as if they were upright on the ground.
The performers continued, taking no notice, but the spectators could not help laughing merrily.
From crowding into the library to witness the fun, intending spectators had to view or hear the proceedings from outside the door.
From a terminological point of view one could argue that this type of music often occurs offstage - 'stage' meaning the space visible to the spectators.
The actual spectators will be more or less receptive to the ways of perceiving or structuring the experience that these layers make possible simultaneously.