I am puzzled by a discrepancy between the content model for the label element and its definition and discussion in the Guidelines. 

The definition restricts the use of 'label' quite narrowly to a list ('contains the label associated with an item in a list') and refers the reader to section 3.7 Lists.

The content model, however, is much more relaxed. While you can't put much into a label, you can validly stick a label just about anywhere and use it more or less like an html heading. You can use it to label paragraphs, you can also use it as an informal way of grouping parts of a div without formally tesselating it into sub-divs. 

Are these loose, but valid uses of 'label' proper? If so, the Guidelines should say something about it. I have certainly seen cases where they come in handy