Rooting your Android device will prevent you from seeing movies rented from the Android Market
Those with the Android 3.1 flavored Motorola XOOM who have rooted their tablet are seeing an error message that reads, " "Failed to fetch license for [movie title] (error 49)" when trying to rent a movie from the application. In a response to a question about the error message, Google says that, "rooted devices are currently unsupported due to requirements related to copyright protection." What doesn't seem to make sense is that Google blames the movie studios for creating this policy while other rental services like Netflix and iTunes will work on rooted devices.
source: AndroidMarketHelp via Engadget