electronics, pretty easy to get inside them and put them back together, normally a good amount of space.
I work with computers a bit, and its very easy to just slide the side panel off and stash stuff. You can even screw the panel back on afterwords so really only someone who knew it was there will get at it.
Another place was the tape deck on my stereo radio in my room, There was a screen to look and see if there was a tape in the deck, so I just put a black piece of paper on the window. Even getting 5 inches from the window you can't tell its a piece of paper, or that there is something in the deck. I'd have to pad down the sharper parts in the tape deck with just cotton balls or w/e so it wouldn't cut or rip the bag.
Then if I was lazy I would just put it in sun-glass holders and put it wherever.