Corollary to III: If thou playest the harmonica, accordian, autoharp, hammered dulcimer or any instrument not readilly retuned (however perfectly tuned and at standard pitch) and the session has settled in at a different (although possibly erroneous) pitch, thou shalt listen with calm repose and withhold even thy most inspired tones.

Special purpose commandment for bluegrass festivals:
Unless specifically invited to do so, thou shalt not jump into a session if your instrument is already represnted in the group.

The commandments are great. They should be printed on every poster, festival flyer and invitation.

      - Mark