H43 and header cell relationships

When marking up a table with multiple levels of headings, is it mandatory to always put all header cell IDs into the headers attribute of a cell?

For example, if a data cell has 3 header cells, but the 2nd header cell's headers attribute references the 1st header's ID, would it not suffice for the data cell to just reference header cells 2 and 3, since header cell 2 references header cell 1 (thus creating a relationship already)? Or must every header always be identified for every cell, no matter what?

Reference: http://www.w3.org/TR/2013/NOTE-WCAG20-TECHS-20130905/H43

Received on Wednesday, 19 February 2014 21:10:02 UTC