I was shooting with one hand and the thing I was shooting was in my other hand (and I don't have the steadiest hands). I usually don't do that, but...come on. Also if it was in landscape mode, you wouldn't see the entire length of the chain unless I was farther away.
Edit: Honestly, I'm kind of annoyed YouTube doesn't have a player option for portrait videos yet, where it doesn't just jam it in the middle of a landscape video player.