RCW 62A.2-512: Payment by buyer before inspection.

(1) Where the contract requires payment before inspection non-conformity of the goods does not excuse the buyer from so making payment unless

(a) the non-conformity appears without inspection; or

(b) despite tender of the required documents the circumstances would justify injunction against honor under the provisions of this Title (RCW 62A.5-109(b)).

(2) Payment pursuant to subsection (1) does not constitute an acceptance of goods or impair the buyer's right to inspect or any of his or her remedies.