From HTML WG Wiki
Aural-oriented and other UA treatment of LABEL and @for in form controls
Research is needed to understand how UAs handle the association of control labels (LABEL) to form controls (e.g., INPUT or SELECT). HTML5 proposes adding explicit markup for LABEL elements by including the control inside the LEBEL element (in addition to using the @for attribute on a LABEL element). While possible in HTML 4.01, this was not explicitly discussed in prior recommendations. In other word, even though prior recommendations included the possibility of adding a control to the content model of an element, they did not discuss the meaning of this explicitly. UAs may therefore have not implement the HTML5 proposed interpretation. Of particular interest are those UAs listed in the UAs#head-51b1bb3a7052bf0c88ade6cf5f07ad426b829ca7: Accessibility-oriented UAs & Third-Party Assisstive Technologies section.
relevant email threads
HEADERS, FOR whom - any ID
Discusses specifically JAWS treatment of using either @for attribute if available or relying on heuristics that do not include a control inside a LABEL element.
- Steven Faulkner (August 2007)