I wonder how hard it would be for Facebook to allow dissidents to set up a second password that logs into a version which hides certain types of incriminating i

I wonder how hard it would be for Facebook to allow dissidents to set up a second password that logs into a version which hides certain types of incriminating information. The trick would be making it indistinguishable from the real thing. (This idea is very similar to TrueCrypt's hidden volumes.)