Md. Code, Commercial Law § 18–305

Except as provided by § 7-601 of this article, a warehouseman or his officer, agent, or employee may not deliver goods out of the possession of the warehouseman:

(1) With knowledge that a negotiable warehouse receipt, the negotiation of which would transfer the right to the possession of the goods, is outstanding and uncancelled; and

(2) Without obtaining the possession of the warehouse receipt at or before the time of the delivery.