I am glad to see this issue raised as it is a bug bear of mine. As someone who is registered blind, I have been moved from the exit row a couple of times. The practice of charging for exit row seats bugs me big time since I can’t purchase them since they discriminate against disabled passengers. I would have thought that such discrimination would be illegal and I would love to see a test case on this. it might force airlines either to abandon exit seat charging or to offer more extra leg room seats that are not in exit rows (my preferred solution).