D.C. Code § 28-3807: Negotiable instruments prohibited.

(a)

In a consumer credit sale, no seller shall take or otherwise arrange for the consumer to sign an instrument, except a check, payable “to order” or “to bearer” as evidence of the credit obligation of the consumer.

(b)

Any holder of an instrument prohibited by subsection (a) of this section 28-3807, if he takes it with knowledge of a violation of this section, takes it subject to all claims and defenses of the consumer up to the amount owing on the transaction total at the time of the assignment.