I'm building a small quiz application (something like "what song is this?") with embedded YouTube videos. But the questions are too easy if you can see the video (the answer could be in its title). So my idea is to hide the player with a div so you can hear the video but not see it. The div disappears and the video becomes visible as soon as you pick an answer or click on "Show video".
This is optional, before starting the quiz you can check an option named "hide the videos to make things harder", and if you don't the videos are normally visible.
Now, hiding the embedded video player sounds like something that could violate YouTube terms of service, but I can't really find information about this. Any thoughts?