In the scene where Luke, Han, Chewbacca, C3PO, and R2-D2 have been brought to the Ewok's village and are trying to talk their way out of a bad situation (mainly being the main dish in C3PO's honor), watch the ropes holding R2-D2. In some scenes, he is tied to the structure that the Ewoks carried him in on, in others, he is standing freely, and then later he is back to being tightly bound. I know R2 has many tricks under his dome, but I didn't realize the force was so strong within him--hmm, maybe the Ewoks were worshipping the wrong droid.