The resource identifier should uniquely identify the resource being described by the representation. PATCH literally means "Use the resource at this URI, but ap

The resource identifier should uniquely identify the resource being described by the representation. PATCH literally means "Use the resource at this URI, but apply the enclosed state representation to some subset of that resource." In that way, the state representation being sent only actually represents a subset of the resource being identified. I'd argue that this semantically makes the actual target of the new state a resource in itself and it should have its own identifier.