You can differ all you want. You are mistaken. In fact, a few older burners didn't even support -R at all, but that has little bearing on anything. I respond to people who use inferior quality blank media on a daily basis here on the forums, regardless of whether they use -R or +R. Most don't know any better--and many people also don't know whether the firmware in their burner supports the blank media they're using. This accounts for many users' issues with blank media, regardless of whether they're using -R or +R.