This is pure bullshit. EME doesn't change how something is rendered, only whether certain content can be delivered at all. And we already have existing standards-backed cases where different platforms get different content (or no content at all). Coincidentally, it affects the exact same thing EME does: media rendering. I can deliver an H.264 video and be standards-compliant, yet rendering differently in Safari vs Chrome (because Chrome refuses to support H.264).