In the preparation of the list of producers or handlers to be used in the formulation or amendment of any marketing order or marketing agreement, the director may omit from such list the name of any person that makes only casual sales of the product which is involved, or whose sales or marketings of such product are incidental to urban home ownership, or the result of activity other than a commercial farm or business venture. Any person that is excluded from such lists is not subject to the provisions, including the payment of any assessments, which are applicable upon producers, or handlers, as prescribed in any such marketing order or marketing agreement.