I'm coming in late to this thread but I used to work for a company that sold educational technology to schools and univiersities, and we sold a lot of the DLP projectors. Those manufacturers tried to spin the same bullshit, but I believe it came out as a defect in the chip that Texas Instruments manufactured that some of these projectors would develop either black or white "bubbles" after 2-3 years of use. They tried to claim they were isolated incidents and easy to ignore but more often the dead pixel issue would spread until the image quality was severely compromised. I doubt the switch uses the technology, but either way, dead pixels aren't easy to ignore and usually get worse.