You'll need a removable volume to see this.  I used a USB hard drive.

1. Clear the trash.
2. Mount the removable volume.
3. Copy some files to the removable volume.
4. Move the files from the removable volume to the trash and notice that the
desktop trash icon indicates the trash has something in it.
5. Unmount the removable volume and physically remove the device from the system
(on a USB device, this means unplug the device).
6. Notice how the desktop trash icon is not updated--it still indicates there is
something in it but there is not.  Even if I open up the trash directory
(trash:) I see 0 files in it but the desktop trash icon doesn't accurately
reflect this.

At this point, Nautilus has no way to actually empty the trash.  The files were
in another trash directory which is now not reachable.  So the trash is empty
and the trash icon should reflect this.

What should have happened: The trash icon should get updated every time a
removable volume is mounted or ejected/unmounted.

I'm trying this on an updated Fedora Core 3 GNU/Linux i386 system.  My hardware
is an Asus P2B-D with 2 500MHz Pentium IIIs and 768MB RAM.  I'm using the
built-in USB ports.