XHTML 2 Role Tag

Hi;

I've just been discussing spatial relationships and other semantic encoding techniques on www-svg, and this led to a thought on the proposed role tag.

Whilst the semantics of the role are conveyed by the proposed tag, I don't see how it covers other encoding channels such as spatial relationships.  For example, there could be an advertising image to the left of a block of text.  The semantic meaning conveyed by this relationship may be that the image is an advertisement for the text content, ie. a picture of a product and some blurb about that product next to it.

Is it upto the role tag to provide this level of precision in specifying the role of something?

Thanks,

Will