One of the most intelligent case studies in design is the Chinese tea cup. They’re made without handles simply because if it’s too hot to touch, it’s too hot to drink.
Humans naturally want to add more. Add a cardboard sleeve, add a warning on the outside of the cup, add a handle. The result of all these things never cools down the actual contents. And in the end, you’ll still burn your mouth from drinking too early. It’s not that people don’t see the warnings, we’re just adding more layers of separation between us and the answer.
Simplify until it’s obvious.