1 the hardware, this support program could work only for certified hardware and using certified drivers, no latest nvidia driver beta(I got kernel crashes because of video drivers both on Linux and Windows and the blame would be on the driver vendor)
2 Some users are stupid, if you ever did customer support you will know (in one case a person complained our application was missing a button, in the end I use TeamView to see the weird issue and guess what, the user dragged the window down so the button was offscreen, this is maybe a Window Manager but , it was on Windows or Mac I do not remember) my point is your customer support team will waste a lot of time so the support program can be expensive.