Auto mounting USB device works (sometimes)

[Tony]

I have recently been using my (USB) iPod shuffle to load podcasts.

I have noticed that when my machine has recently been booted, it will
auto mount my iPod shuffle to /media/iPod OK.  However, when I try
later, like the next day it will not mount the iPod.  If I reboot the
machine will do fine again until it has been on for some time like
overnight.

Has anyone else experienced this with a USB iPod shuffle or other USB device?