That is not even the worst of it. They provide no UV protection. A lot of people think that just because the glasses are dark they provide a similar amount of protection compared to more expensive sunglasses. However, you are actually better off not wearing sunglasses at all, since at least you will squint and avoid looking directly into the sun. Wearing "fake sunglasses" is something that is just generally not advisable. You are better off wearing a pair of cheap safety glasses.