Hi Alex, thanks, but I'm not sure we're talking about the same thing.
Here I am (a premium member) calling a non-premium member within the messenger. (premium INITIATING the call)
Now, here is the standard (non-premium) member, trying to accept the call -
As you can see, a NON-PREMIUM member can't join an existing call.
The intention is to allow standard members to join existing calls, which a premium member initiated.
The best case scenario is to simply have an extra option in permissions, to separate between -
1) Allow to START (Initiate) video conferences
2) Allow to JOIN existing video conferences (1 on 1 or group calls)