And why videos in the first? Why not a photo? It would cost less time and can be taken anywhere (toilets f.e.)

I just don't get, why do you want to make it difficult to access the app (at first take your time to record a few seconds). Then why pollute an experience with recordings that wouldn't have mich creative input, because they're just for gaining access ("cooking smthg", "waiting for smth", "want to have a short look what my friends are doing and need to record smth.") - you'll never get an Input like "how the earth have evolved", as this is content, but you'll have faces at first.

What happens if one accumulates say 1k friends. Will he look at "access denied" faces the whole day?

The idea seem to solve a non problem: User engagement through access Control. If you ask me, I try it once, bur then go back to the other social apps.

Just because there I can consume.