Thanks for your reply. I understand your point but I think that shouldn't be a big deal to members who are creating a Video Conference. When creating a video conference, the system can grey out (or hide) the option 'to add a participant' on accounts/members which are not allowed to join the Video Conferences making it impossible to the video conference host to add them. Alternatively, the system can also advise the Video Conference host through an action denied message that that member doesn't have the permission to join a Video Conference. Isn't it feasible? 

It is just like trying to invite or add an offline contact/User to a Conference call. Many communicators like Skype won't let you to do so.

Thanks.