I didn't mean for it to be used in a high level directory recursively, that would surely break things in spectacular ways. You should make a separate private folder to keep things you don't want seen. Although i guess using -R is good if you make sub-folders there
Anyway, this is nothing more than a simple hack to keep nosy tech-oblivious friends away from your more intimate pictures with the missus or the shopping list. It will do nothing to stop more advanced users. And it will not work on vfat at all (no permission/ownership support on that piece of junk)
Also, i understand most people want a tightly integrated 'secure mode', where they only have to flip a setting and enter the password. I'm afraid even if the infrastructure was there (gpg, encrypted loopback interface and all), the user would still have to do the securing (for example, pictures will have to be moves/encrypted-decrypted manually, unless the camera app is changed to take care of that, which i kind of doubt)