Reasonable people may disagree.  I believe that sequence and 
containment are purely syntactic in nature and imply no semantic
whatsoever.  Similarly I see no "semantic" in asserting that my butt
is currently placed on top of a chair, or that this chair is currently
placed in front of my computer.
>it is disheartening to read where attention is deflected from the issue by
>claiming that no semantic was intended. 
Get real.  You may choose to argue that containment and sequence 
constitute, in some philosophical framework, "semantics", but the claim
that no semantic was *intended* is unchallengeable because in point of
fact when we wrote the spec we considered that what we were describing
was syntax. -Tim