Why do people assume that deniability results in more whacking?

Technology can easily be used to encrypt a hard drive to reveal different things for different passwords. TrueCrypt does it.

Plus you can have cryptographic keys stored with friends or beacons that signify you are safe. For example you hide files on your phone before a flight, and to unhide them you need your host's wifi at your destination.

Until the friend or beacon gives the ok, you can either have your phone LOCKED or have all sorts of files that are encrypted and HIDDEN. The computer can be unlocked but won't show those files.

Why isn't this technology widespread? YOU CANT WHACK EVERYONE!