The content model for <respStmt> is:
( ( resp+, model.nameLike.agent+ ) | ( model.nameLike.agent+, resp+ ) )
But the prose (3.11.2.2) says “At least one of the four naming elements (name, persName, orgName, or rs) and one resp element should be given within the respStmt element, followed optionally by any number of any of them.”
I.e., the prose implies a content model of
( ( ( model.nameLike.agent, resp ) | ( resp, model.nameLike.agent ) ), ( model.nameLike.agent | resp )* )
The question, of course, is whether to change the prose to match the content model (my vote), or the content model to match the prose.
The prose content is much looser, and to my knowledge no one has ever complained that the content model is too restrictive. (And I've even argued it's too loose. :-)
Fixed (by altering prose to match content model) in [r13020].
Related
Commit: [r13020]