Oliver, thanks for your response. I completely agree regarding tab navigation of pages and the fact that users often use headings to navigate content. No point of contention there. Though it's also true that my client has run into some cases where tabbing is happening instead of the arrow nav dictated by WCAG. Within form elements, for example, dropdown menus, cell-to-cell navigation in tables, radio buttons in a group) where navigation of the child elements should happen with arrow keys and not tabs if we're really going to conform to WCAG 2.0. 

For anyone looking for a way to prevent the span behaivor comes across this issue, change `isAriaLabelFixEnabled: true` in `core/js/accessibilty.js` to `false`. The default with this fix disabled is for the aria-label to remain applied to the parent div.