But how is it considered trustworthy? That's basically the central struggle every media organisation has right now and I don't see an easy answer.

Yours is an interesting idea, though. I dread to think how much it would have to exclude though - probably have no Android client because I'm sure a rooted phone could easily provide a fake video source. Maybe even on a jailbroken iOS device too. And once that becomes possible the entire platform is ruined.