Why would you go through the trouble of backing up data and reinstalling the OS when it would most likely take less time to crack the password than it would to back up the data alone? I don't see any negative effects of cracking the password (besides possibly realizing how insecure the password is), and if it's not an incredibly strong password, everything could be back to normal within five or ten minutes, rather than the few hours it would take to back up, reinstall, and reconfigure.