When using the Vidyo panels (ipad or touch screens) in meeting rooms there's no way to see a list of participants. This is useful in scenarios where people have their webcams disabled but are present in the conference, or join/leave with the webcam disabled. You cannot tell who has just joined or left. There are also scenarios where we need non-Mozilla people to leave before talking about confidential information and we can't be sure that all participants are Mozilla-only. It could be either a menu option on the control panel or a transparent overlay on Vidyo itself. If you are logged into Vidyo via the desktop app you can see a list of participants so such a thing exists in Vidyo somewhere.
We are looking for a way to do this, but will require an API change from Vidyo.
This is currently on a feature request list. Will not be able to add until late 2017. Will roll out when available.