The fields of cryptography and communications are quite distinct and while communications systems often combine technologies from the two fields, a layered architecture is applied that permits each layer to be independently designed. It is generally agreed that watermarking, i.e. the embedding and decoding of messages within content, is a form on communications, and is often modeled as spread spectrum communications or communications with side information. However, despite this, the layered architecture is not always present. And perhaps more concerning, an number of analogies to cryptographic concepts have been made which, we argue, are misleading or incorrect. In this paper, we highlight these analogies and discuss why they are inappropriate.