Toyota engineers took note of the many threads and complaints of the first Gen and early 2nd Gen owners regarding the TC system. Through the 2005 MY Prius it certainly would be possible for the TC system to override your efforts to rock and roll your way out of a mess.

Beginning with the 2006 MY they made a change in the TC system that allows the wheels to slip somewhat to allow movement. The complaints seem to have gone way down since then.