Edit: it seems that this is a known bug and that it is impossible.
How can I disable the 'unmount' option for my second internal harddisk in Ubuntu?
My system consists of a 128GB SSD and a 1TB HDD.
The reason I want to disable this button is to prevent accidental clicks when I'm clicking the unmount buttons for USB sticks that I'm unmounting.
There is absolutely no reason for me to unmount this internal HDD, yet I still see the 'unmount' button (underlined triangle) in my Unity filebrowser side pane.
Here is a snippet of my /etc/fstab:
# <file system> <mnt> <type> <options> <dump> <pass> /dev/mapper/ssd-root / ext4 noatime,nodiratime,errors=remount-ro 0 1 UUID=8e645641-889d-4eec-b356-8fe90d683bf8 /boot ext2 defaults 0 2 /dev/mapper/ssd-swap_1 none swap sw 0 0 /dev/mapper/hdd-storage /media/storage ext4 noatime,nodiratime,errors=remount-ro 0 1 /media/storage/home /home none defaults,bind 0 0 /media/storage/var/log /var/log none defaults,bind 0 0
EDIT: Setting the mount location from /media/* to /mnt/* solved this issue.