Re: Technique 5.1 (Table Headers)

> The guideline specifies that there should be row and/or column headers for
> *data* tables only.
> 
> Shouldn't there be headers for tables used for layout?

No, see Checkpoint 5.4.
 
> How could we determine if the table was a data table or a layout table?

Heuristics.
Most tables are layout today.
Likely to have size specified (width, height), colspan, no border.

Data table are likely to have tr and borders.