Possibly. We can't backpropagate through all the neurons in a human brain. If we could we might be able to create real BLITs http://www.infinityplus.co.uk/stories/blit.htm .

I do not think there is a one-to-one connection to be made between neural nets and the brain. That said, it is possible to fool our own visual system in a similar way: http://en.wikipedia.org/wiki/Gestalt_psychology#Properties

If you haven't seen this picture before: http://www.moillusions.com/wp-content/uploads/photos1.blogge... it should appear as meaningless noise. After you spot the Dalmation dog, you will notice it in the future.

I think so, we just also have the capability to "double take" and pay closer attention and get a new point of view when the thing we're seeing is unexpected.

Its hard to say if a similar hack would work on people since we can't easily run an high speed optimization over the human visual cortex. Maybe some mice?