Cast iron isn't completely without risk. The iron from the pan can leach into food which can be a problem for people with high iron issues. On the flip side people with anemia could see some benefit. My personal favorite as someone with hemachromatosis is enameled cast iron.

I definitely thought it looked like a microscopic cat walked all over the sample.

In many cases schools are legally considered in place of parents meaning they can give certain consents for the underage attendees such as approving of search and seizures of their private property. https://www.law.cornell.edu/wex/in_loco_parentis

And before 2008 it was the after effects of the 1999/2000 tech bubble bursting.