What if you bought an ice cream cone and it was so cold that you had to get skin grafts to repair the damage to your lips? And not only that, but the owner of the store instructed the employees to make it that cold?
The McDonald’s woman’s risk calculation was probably “if this spills, it will hurt” and not, “if this spills, it will do permanent, significant damage to my body”.
Why would anyone prefer living in a world where some property of any item you buy could intentionally be set to dangerously extreme levels?