Viewing behind TOR or similar platforms might eschew detection during viewing (but not necessarily after the fact). It's unclear whether https encyption alone would do so.
Since YouTube videos are often UGC (user-generated content), there is no guarantee, from the viewer's knowledge, that the actors were age verified. But Section 230 would not protect the platform from downstream liability in c.p. cases (and now trafficking has been folded in to the liability risk with FOSTA), so users might be entitled to the belief that the platforms take some reasonable care to remove what they reasonably suspect is c.p. or illegal, even without age verification of actors presented in all cases.