We already knew that the other “advantage” of switching to DisplayPort was that this standard includes HDCP (which is, basically, DRM on your TV cables), so owners of new MacBooks shouldn’t be surprised that their laptop uses it; there is a surprise, though, in how many of iTunes Store downloads include HDCP — and you can play them from an older Mac onto any secondary screen, but a new MacBook will only play them on the internal screen or the upcoming 24-inch DisplayPort Cinema Display.
People are reporting this on non-HD movies though. That seems likely to be a bug. No studio should be enabling HDCP on SD movies. I doubt that it is intentional.
Considering that iTunes gleefully ignores HDCP if your computer doesn’t handle it — and that Apple’s only HDCP-compliant monitor is only now beginning to ship — it’s hard not to see that as a bug that’s going to be fixed.
But then, in the world of DRM, there’s no such thing as common sense.