There's another instance of blitting a surface to itself crashing on Windows for a user, it's believed to be a 1.8.1 thing by the poster
http://pygame.motherhamster.org/bugzilla/show_bug.cgi?id=19
last time it came up marcus was thinking about making pygame throw an exception on blitting a surface to itself, which still seems like a decent solution to me. Anybody know any more background?