Both these programs currently have the ability to link to external files using hyperlinks in a feature data field. However, the URL/UNC does not appear to be respected if the hyperlink uses a UNC pointing to a local resource. For example this UNC (from an Android device) would not work (the program doesn't recognize this as a hyperlink).
This would be extremely useful in the Collector app, especially if the Offline capabilites (when they become available) are to be utilized. Please make these programs respect hyperlinks and allow linking to local files on mobile devices using UNC path names in feature data fields.