You are using Ubuntu 12.10 right? Um ... I don't think it is automatically mounted. At least not automatically mounted at boot. It may appear that way because it's listed in Nautilus and when you click it it just brings you to the contents of that partition but what it's doing in the background is mounting it for you when clicked.
The shared primary partion is automaticallly mounted in /media/USER (not sure how with no fstab entry)
The reason I think that is because no human would ever mount anything under /media/$USER ( look at the permissions of /media/$USER and you will see why ). If you decide to use symlinks or bind I would have the partition mount automatically in fstab and I would mount it somewhere else like /media/shared or even /mnt/shared. For example:
Create a mount point in /mnt:
Add a line to fstab ( note this line should appear above the bind lines in fstab if you are using bind):
sudo mkdir /mnt/shared
To find the correct UUID number for your partition run this command:
UUID=DA9056C19056A3B3 /mnt/shared ntfs defaults,nls=utf8,umask=000,uid=1000,windows_names 0 0
Unmount the already mounted partition:
sudo blkid -c /dev/null
Then run this command which will test for syntax errors and mount the partition:
sudo umount /media/USER/shared
If you use bind you will need to change the path to point to the new mountpoint: /mnt/shared/Picutes for example.