Whenever I'm about to park my car (lets say im going to taco bell) i "undock" the tablet from my mount and just throw it under my seat. i hide the audio wire that i feed to it and that's it. if someone looks inside my car, they dont see a thing.
the other thing i do, since my laptop is purely black in color, is i put on the floor of the rear seats... why? the rear windows on my car are tinted and you cant see the floorboard from the front untinted windows. if someone looks in to the back windows, they just see black - nothing shiny or anything like that.
I do this maybe at the light (or second light) before my destination. When I am parking my car, i take the tablet with me!
I thought about making a semi hidden area to put the tablet... we'll see what I come up with ;]