Prevent BootCamp partition from automatically mounting
Your original solution using /etc/fstab will work, but you must use the volume's UUID (which DOES exist, Disk Utility just doesn't display it for NTFS formatted partitions- thanks Apple...)
To learn the UUID use the following command in terminal:

diskutil info /dev/diskXsY  ##substituting the X &amp; Y for the disk and partition designation of the volume you want NOT to be mounted- which you can learn with: diskutil list

For this command to succeed and show you the UUID you can not have Tuxera NTFS enabled for that partition.  If you are using that or probably any other non-native file system drivers for NTFS, you must disable them (at least for that partition) and reboot.
The partition must also either be mounted or dismounted when you run the command- I can't remember which (and I remember that for me it actually turned out to be the opposite of what I found posted on a forum somewhere... so experiment).

If for some reason you just can't get OS X to show you the UUID you can resort to booting up with an Ubuntu installation disk and using a tool like gparted (there are quite a few ways using either the command line or a GUI app- you won't have trouble finding more information on that).  You don't have to worry, the UUID will be the same between operating systems.

Then add the following line to /etc/fstab

UUID=(you know what to put here- no enclosing brackets or anything) none ro,noauto 0 0

reboot and voila- no unwanted partitions mounted!  This is a system wide setting for all users, but you can still mount the partition using the Disk Utility.

This is the most pervasive and effective solution to this problem- plus it's not broken if you happen to move the disk to another controller or port, or even if you change the volume's label.  However, formatting the partition will assign it a new UUID.