Does the assessment fee apply to accounts of persons having "privileges of membership" on a contract market?

No. NFA Bylaw 1301(b)(i) makes the NFA assessment fee inapplicable to trades of customers who have "privileges of membership on a contract market where such contract is entered (except that this exemption does not apply to transactions by commodity pools operated by NFA Member CPOs)." If the exchange formally recognizes the customer as a member and charges exchange fees at the member rate, the NFA assessment fee does not apply.