Are you saying they're lying or are wrong about this? They seemed to have personal experience about it, and I'm assuming they're not outright lying, but I do think it sounds strange they would let children sit and code for 3 days straight.
But that's beside the point - they provide rooms, plenty of food and snacks, workshops, and activities to do during breaks. Organizers are on-site at all times, and there is a live hotline for parents or kids to call at any time. "sit and code for 3 days straight" is a gross mischaracterization.
Here's an example of an event hosted: https://www.youtube.com/watch?v=uXWMr0gdLJA