This seems like it could be a practical application of ACCESS by Marie Sester.

The proposal was pretty coherent. Obviously there would be some issues with implementation. Jeff mentions that a photochromic material might hold the laser image for a short time before fading away. The personal aspect is really good. I like the idea of the fish. To work, you would really need to track the position and identity of lots of people, but the is probably possible.

I wonder if audio could be integrated. When you think about the human guide, it makes me think of a voice that whispers just in your ear. Could be done with sound beams.