I found a very interesting essay on early Intermedia practice by Al Hurwitz from March, 1970:
No one should embark in any role in intermedia if he is unsympathetic to the apparently antisocial conduct of youth or if he is easily threatened by seemingly bizarre and egocentric behavior. Avoid interermedia if you see yourself as an "authority" figure or if you don't know how to listen. Don't get involved if you are afraid of criticism of outsiders, if you need a blue print for the future, and if you place no trust in the unknown. Intermedia, like any art form, is not for the timid, nor is it to be undertaken lightly.