There are always people who just can't wait for 10-20 seconds for a boss cutscene, and this is sad enough as it is.
But reporting a newbie for not skipping a cutscene is a new level of being petty. This community really never fails to disappoint.

But to be serious, I just can't imagine a report like this would go through. I doubt any GM in their right mind would ban someone over watching a cutscene, something the game itself offers you to do and is part of the whole experience.