Well, phooey. Google is blocking users with rooted Android devices from renting movies via Android Market. Apparently, it's "due to requirements related to copyright protection". I guess Google thinks people who use rooted phones are pirates who steal movies.
It's not a wide user base getting screwed by this (after all, Android 3.1 is only available on the Xoom and Android Market movie rentals aren't yet available on Android 2.2+ devices) but it's a user base that is rooting phones to get more out of their devices and very likely the people who love the freedom that comes with Android. Screwing them is silly, especially since they'll eventually find a workaround anyway. [Android Market Support via Android Central]