Of course you have. But then you realized just how much work it would take (and how much a pain clean-up would be), and decided it wasn't worth the effort.
We came up with a better way. Here's how to make them think you've actually done it.
1. Roll of tape
3. Roll of paper
4. Packing peanuts
5. Small box with at least 3 flaps intact
1. Roll out a strip of paper horizontally along the bottom of the frame
a. Be sure to leave enough space for the tape to overlap the bottom of the frame so the peanuts don't spill out the bottom
2. Tape left, right, and bottom edges
3. Fill the box with packing peanuts
4. Open 3 flaps with the one at the bottom inside the paper
5. Pour peanuts in
6. Pat the paper to help 'settle' the peanuts to fill in the gaps so you don't see the paper backing
7. Roll out next strip of paper
8. Repeat steps 2-6 as necessary
9. To finish it off leave some slack at the top so it bulges out a bit
a. This helps to give some depth at the top so you can make a pile of peanuts at the top, aiding the illusion
1. Close the blinds - too much light bouncing around the room reduces the illusion
2. Stuff packing peanuts under door - blocks light as well as discovery that the room is actually empty by peering under the door
3. Rig paper 'tube' from door frame to back of door and fill with peanuts, spilling out when the door is opened
4. Place something heavy behind the door - gives resistance when the door is opened
5. Rig a waterfall of packing peanuts to spill out when door is opened
Thanks to Jim and Paul for masterminding the operation; double thanks to Jim for writing up the instructions, and to Chris for being a good sport!