This issue is occuring on more than one Mac (one at home and one at work). Magic Mouse preferences are locked. They're locked on with an iMac and locked off on a Mac Mini. In both cases, changing the mouse preferences does nothing. Both are running 10.9.1. There was no problem before Mavericks.
iMac, OS X Mavericks (10.9.1), Same issue on Mac Mini and iMac