User Configuration > Administrative Templates > Microsoft Word 2016 > File Tab > Check Accessibility
User
HKCU\software\policies\microsoft\office\16.0\word\accchecker
This policy setting prevents the Accessibility Checker from verifying that tables have a header row specified. If you enable this policy setting, the Accessibility Checker will be prevented from verifying that tables have a header row specified. If you disable or do not configure this policy setting, tables will be checked for header rows and any issues will appear in the Accessibility Checker.