> The University of Michigan recently banned employees from sitting on yoga balls due to “catastrophic failures.”

I mean... they had enough of these balls pop while people were sitting on them to decide to ban them. Do you really believe that most of these, which are probably bought on Amazon, etc., are all made of the highest quality materials, and testing using rigorous QA methodology? Chances are, people are buying the cheapest, $10 yoga balls and not trying to find which one will last.