This is still always your avatar name - code to set a different display is not yet implemented.
This works from my testing with current Firestorm and Singuarity releases.
This is to match existing behaviour with UDP behaviour where this is masked out.
And to make it consistent with other places where viewers mask this out themselves.
Relates to http://opensimulator.org/mantis/view.php?id=7408
Unexpectedly, not setting user name achieves this whereas one might have expected it to be done by not setting display_name in the cap OSD.
Emulates LL behaviour when no display name is set.
Relates to http://opensimulator.org/mantis/view.php?id=7408