I see your point but I assume the producers of the hack own the rights and IP to their work i.e. there's nothing stopping them releasing what they did as open s

I see your point but I assume the producers of the hack own the rights and IP to their work i.e. there's nothing stopping them releasing what they did as open source and building a community around it (at least that's been the case with every hackathon I've ever participated in). If the above assumption is true then I don't see the problem. ArcelorMittal get some buzz and maybe some ideas to pursue, the hackers get a fully paid fun weekend and a little cash for their efforts, society potentially benefits from the seeds that were planted.