Amazon has a cover for KFHD that locks/unlocks the screen for you.
And Paperwhite still has swipe to unlock unless you use a cover that does that for you.
Kindle Touch does not have swipe to unlock, and it is a problem, especially if you don't have a cover. And it doesn't have a sensor to work with an 'active' cover. I set a one digit passcode as a workaround.
If you aren't using a cover, you definitely want swipe to unlock. Otherwise an accidental bump to the power button can turn it on and the screen will start responding to things in random ways as it rattles around in a pocket or purse.
Last edited by tomsem; 01-16-2013 at 10:54 PM.