The navigation application (and I guess the other Apps using pulse) do not require any privilege to play audio.

Access to gst-launch is protected.

see call in 

  /var/local/lib/afm/applications/navigation/0.1/flite

------------------------------------------------------------------------------------

I have replaced in the shell file
/var/local/lib/afm/applications/navigation/0.1/flite

the call for paplay by gst-launch

paplay --property='media.role=Navi' $TMP /usr/bin/gst-launch-1.0 filesrc location=$TMP ! decodebin ! audioconvert ! audio/x-raw,channels=2 ! alsasink device=Warning

rm -f $TMP

I keep the file to test in command line.
In command line is works (obviously I have corrected the pulse config file to leave Navigation to Alsa /etc/pulse/default.d/90-4a-modules.pa)

But when used from the Navigation App it fails due to a "Not Authorised"

cynara[272]: User::App::navigation;0;urn:AGL:permission:audio:public:audiostream => DENY