When I insert a thumb drive, media card, or USB hard drive, to unmount it via the command line, I need to use
sudo umount /media/the_device
But, I can unmount the device in a file manager like nautilus simply by clicking the eject button or using the right-click context menu on the device.
What is the rationale for the difference? How can I change it so that I can unmount from the command line without needing root privileges? Is changing it a bad idea?
Edit: In case it has changed, I am running 9.04. I've run most versions 5.10--9.04, and as far as I recall, it has always been this way.