I have a teenager who is at an academically rigorous college prep school. He is incredibly bright and one of the best students in the school. But he has an accommodation in math for extra time because he has a form of dyscalculia which makes him very prone to misreading and mixing up in working memory the numbers, symbols and other formulas. He understands all the concepts well, but his disability results in calculation/mechanical errors unless he has the extra time to check his work multiple times for these errors. I believe this kind of disability and accommodation is legitimate, but I understand why others may disagree. He even says he often feels guilty for getting extra time when others don't. I am sure there are also people who abuse the system and get accommodations when then don't actually need them.