JAWS doesn't read either alert. According to http://www.w3.org/TR/wai-aria/roles#alertdialog, "authors SHOULD set focus to an active element within the alert dialog, such as a form edit field or an OK button." Also, "Authors SHOULD use aria-describedby on an alertdialog to point to the alert message element in the dialog," which we are doing. I don't know why the alert is not being read. This represents a step in the right direction, so I think we should go ahead with this change and consult with an expert for advice on improving the experience.