In looking at this spec recently, I found a few oddities...
The specification is not clear whether a stanza can contain multiple <delay/> elements such as when its delayed by multiple entities. While I cannot find any example or discussion of multiple <delay/> elements in any XEP, I assume multiple <delay/> elements are allowed as multiple entities can delay a stanza. But oddly I cannot find any discussion of multiple <delay/> elements in XEP 203 or any specification which calls for <delay/> elements to be added.
Presuming the stanza can contain multiple <delay/> elements when its delayed by multiple entities, the specification language could be read as disallows an entity which delays a stanza multiple times from indicating that it has done so by including multiple <delay/> elements. For instance, when a server delays a stanza to a chatroom (hosted on another server entity) and than delays the forwarding of that stanza to one or more of the subscribers of the chat room.
The specification recommends (in security considerations) that an entity remove delay notices which indicate that they were provided by the entity, or bounce the stanza, without at all noting that an entity should not remove it's own delay notices (or bounce a stanza it previously delayed). IMO, an entity SHOULD NOT remove <delay/> purporting to be from it unless it believes they weren't from it.
There also seems to be issues in subsequent handling of previously delayed messages as well... but first the above.
-- Kurt
