ejecting before disconnectiion should prevent data loss
also the unejected unplugging can "harm" the drive
i unplug my usb drives on windows without ejecting, but i see when it's done doing anything - but iPods are different - and i think it would not harm when you simply click on the eject sign.
if you only want to charge and not sync the iPod - uncheck the autoconnect stuff in itunes. then it will only charge and only when you start itunes on your own - it will connect
When iPod is connected to a computer there are times when it should not be disconnected by simply unplugging the USB cable. The reason is because the computer may still be writing data to the device, removing it prematurely will cause data corruption. In these cases, iPod must first be ejected before it can be safely disconnected.
iPod can be safely disconnected by simply unplugging the cable if the iPod display shows any of the following screens:
"Ok to disconnect"
The iPod main menu with the Music, Settings, and Extras selections in addition to others
iPod shuffle displays a solid amber or solid green LED
iPod must be ejected first before disconnecting if any of the following screens are displayed on the iPod:
"Do not disconnect"
"Connected, Eject Before Disconnecting"
"Sync in Progress, Please Wait..."
iPod shuffle displays a blinking amber LED
If the "Enable disk use" or "Manually manage music and videos" options are enabled for iPod in iTunes, iPod will need to be manually ejected before disconnecting the cable
To eject iPod:
Select your iPod in the iTunes Source list.
Click the eject icon next to the iPod in the Source list or choose Eject iPod from the Controls menu.
Additional ways to eject iPod
You can also eject iPod by using a keyboard shortcut (Command-E)—but only if the iPod is selected in the iTunes Source List.
If the iPod display still shows a screen indicating that it should not be disconnected as explained above, use the method below to eject iPod.
Click the Finder icon in the Dock.
Select the iPod icon.
From the File menu, choose Eject iPod (Command-E).
Double-click My Computer (Windows XP and Windows 2000) or, on the Start menu, click Computer (Windows Vista).
Right-click the iPod icon.
Choose Eject from the shortcut menu.
When I connect my ipod via the UBS lead a message comes up 'connected eject before disconnecting'. I have followed some tips suggesting to hold down both the middle and top buttons, which I have tried. The apple logo appears, then the menu, very briefly and then it reverts back to the message.