I think your whole tangent here is drastically missing the mark, though. The individual concert-goers didn't know there'd be far more people than expected and

I think your whole tangent here is drastically missing the mark, though. The individual concert-goers didn't know there'd be far more people than expected and that local infrastructure and the organizer would be overwhelmed. They saw there was a concert and decided to go, just like every other show anyone attends. Upon arriving, they were stuck in a situation they didn't expect and which people don't expect when they head to a large event that's supposedly "official" . At that point (gridlock, overwhelmed infrastructure), they're without any options beyond asking others for help, because they weren't prepared for a situation that shouldn't have happened. They came to attend a concert, not a survivalist retreat.