Dunno, but
I'll observe that that syntax was probably used rather than
<link> to stop CSS 1 clients from downloading the stylesheet.
Is that for bandwidth or display reasons? It would be lovely if we
could work around this issue in Firefox and IE somehow, as it directly
impacts the usefulness of saved pages for millions of readers. Aside
from the relation between layout and readability, a person who has no
idea what a stylesheet is may, from the very drastic visual
differences, infer that something went seriously wrong with the saving
process, and just give up.
In fact it did go wrong. They may give up if they want, but they will
surely notice that the page content is saved (which imho is what they
will want).
They aren't bandwidth reasons, but compatibility ones.