A shadow partition would be more effective at bypassing customs. For real boots, you use a copy of grub on a usb dongle. When grub is missing, you boot into a honeypot Windows XP partition that was installed only for that purpose.
For this to work, you need to actually use the dummy partition for non-sensitive matters -- and be absolutely religious about separating the sensitive tasks from non-sensitive, which is much more difficult than it first sounds.
There is nothing unusual about that.