Have you ever used flash memory password protectors?
Seperate memory into protected and non protected zones. They place themselves on non protected zone. Each time you insert flash you enter password and you can see protected area. Else Windows only seas non protected part. When you remove and reinsert the flash the drive is locked again.
My friend has bought two Kingstone 32GB DataTraveler drives. When you copy data into them you can see them. When you remove and reinsert the drive. You can't.
I thought its a similar to flash protection situation.