Google, which often touts the "openness" of its Android mobile operating system as one of its primary benefits, is blocking access to its new Android movie rental service to rooted Android devices. Google blames "requirements related to copyright protection" for the move, and this isn't the first time DRM has caused problems for consumers. But it serves as yet another example that Android's openness only extends as far as it benefits Google.

As many Ars readers know, users often "root" Android-based smartphones and tablets to extend their functionality. In Linux-based systems like Android, there is typically a "root" super-user account that has heightened administrative privileges and unfettered access to the operating system. By enabling the root account, users can introduce software components that have been extracted from other Android devices, modify the user interface, and more. It also allows them to install Android updates that device makers haven't gotten around to making available in a timely manner.

In most cases, rooting still allows users access to Google's services, including the Android Market. However, Google is restricting access to its YouTube-powered movie rental service to non-rooted devices. Users with rooted devices attempting to watch Android rentals will get an "Error 49" message, noting that their device was unable to "fetch license for movie."

Google's support documents state that DRM is to blame. "You'll receive this 'Error 49' message if you attempt to play a movie on a rooted device," according to Google's related support article. "Rooted devices are currently unsupported due to requirements related to copyright protection."

The restriction is seen as yet another slap in the face to users who have bought in to Google's claims that the Android platform is superior other mobile platforms because of its "openness."

"Nice move, Google," wrote AndroidCentral's Jerry Hildenbrand. "That makes me want to buy more of your products and use more of your services, so I can be treated like a criminal just because I'm smart enough to get rid of CityID, or want a safe version of Android on my phone."

It's almost certain that content providers required Google to lock down movie rentals to un-rooted devices—Apple, Netflix, Amazon, and others face similar burdens. But locking out all rooted devices seems an odd move, considering that Android was originally touted as a platform that gives users control, as opposed to platforms like iOS that allow few user modifications.

Given the recent decision to hold back the source code for Honeycomb, and the revelation that Google uses its Android licensing terms as "a club" to make device makers "do what we want," this latest move serves to illustrate that Android may not be as open as Google would like its users to believe.