This is a strange one. Presumably a few people in the target group for this would know a few people also in the target group - how do they intend to bootstrap trust? Or is it just a calls b, b's device reject call - b can now call a? Then after b call a, a can also call b?
If so, it sounds like a very complicated way of marking contacts as "super favorites"?
You can receive incoming calls from accounts you have called. Presumably, the bootstrap looks like two people try to call each other, one is rejected, one goes through. Then either can call the other in the future.
Is this really a feature people want? I can’t imagine any situation where I’d want to allow unsolicited FaceTime calls (99% of the time it’s some kind of spammer)