edit: Why the down vote? I was serious - I thought with Youtube Red you could listen with the screen off, am I wrong? Perhaps I misunderstood your screen on statement.
edit2: Well, as others confirmed, it is indeed allowed via Youtube Red like I said. So my post being down voted makes no sense, the OP was wrong. Get your shit together HNer.
edit3: Well, the down vote has been reverted (or upvoted out of it) - regardless, I probably overreacted. To be clear, I don't care about the "Karma" (I try to recreate accounts somewhat often for privacy), I just get irrationally angry when it feels like people try to silence you for an unexplained reason. It's why I hate Reddit.