Added change to address #2287 (#2328)

Co-authored-by: Darrel Miller <darrel.miller@microsoft.com>

versions/3.1.0.md

@@ -73,7 +73,7 @@ A self-contained or composite resource which defines or describes an API or elem
 ##### <a name="pathTemplating"></a>Path Templating
 Path templating refers to the usage of template expressions, delimited by curly braces ({}), to mark a section of a URL path as replaceable using path parameters.
 
-Each template expression in the path MUST correspond to a path parameter that is included in the [Path Item](#path-item-object) itself and/or in each of the Path Item's [Operations](#operation-object).
+Each template expression in the path MUST correspond to a path parameter that is included in the [Path Item](#path-item-object) itself and/or in each of the Path Item's [Operations](#operation-object). An exception is if the path item is empty, for example due to ACL constraints, matching path parameters are not required.
 
 ##### <a name="mediaTypes"></a>Media Types
 Media type definitions are spread across several resources.