I think it depends heavily on how you've been taught to read vids. If it's something I've gotten into, I probably will be able to identify context just because I'll have watched the whole thing recently. But I very rarely find that interfering with watching a vid that takes things out of context. It's all just footage. If someone's smiling, they're smiling. Maybe if the rest of the vid is clearly about a specific episode, it would bug me, but it doesn't usually.