About 40 years ago, on May 28, 1974, in a packed Royal Albert Hall in London, the Portsmouth Sinfonia orchestra held a concert. What's strange about it? They didn't know how to play.
The work “Aus den Sieben Tagen” by K. Stockhausen came to mind; it is not about performing written scores, but each performer, based on the intuitions prompted by Stockhausen's short texts, decides how and what to play. Stockhausen explicitly provides that there are no rehearsals and no direction, asking for the active participation of the musicians' free intuition.