[Corvina]

Wasn't at a-nation or the Jingu festival, but yes, that can happen. It depends where you're sitting though or better who's sitting around you.
Usually people are there for different reasons and festivals are long. Not to mention it's a stadium and there were a lot of people (like 30k maybe?).
Kuu here e.g. was performing near the end and there were surely people only coming for the 1 hour fireworks show starting after Golden Bomber after her.
Haven't watched this video yet, but there are a lot on social media and Kuu was well received though. News reports are saying the same.