There is an ancient survival of the use of @style in the classes documents for historical reasons, and this has given encouragement for the eruption of a plague of such things elsewhere. I've now purged the classes documents and fixed some other problems with them, and tweaked the Schematron a little to allow the use of a plain <label> element for situations when someone wants an inline label (which shows up bold in the output) rather than a block heading. This is a good basis for purging the rest of this pernicious infection.