An interesting point, but you could also say if a young person is able to operate a computer as efficiently as an adult and in some case's better then why not send them to work in an office? Children don't earn money and in most peoples opinion that is why they don't pay as much as adults, they would probably get pocket money from parents and would need to save up for a big event like this. If I had to give a children's entry price I would estimate around £30 for the 3 days.