RE: Heading and labels

I also agree with with Adam that row and column headers in tables are
certainly labels within the meaning of the definition of "label" that he
quoted. I would find it very difficult to argue otherwise - they exist to
"identify" the purpose of the columns and rows. Also the green note
included with the definition says "The term label is not limited to the
label element in HTML". So 2.4.6 can cover many kinds of ways of
identifying what content is - it doesn't apply just to <label> label
elements.

One problem following on from this, that designers cause, is the very
common practice of showing ordering buttons in the column header cells,
after the header texts. I usually recommend they move these buttons to a
new second row of the table to avoid issues with AT announcing them in the
labels.