password protect

As a (very conservative) father to teenagers I would like to see a feature that will enable me to load the music I approve of on my child’s sansa without allowing him/her to add and/or remove tracks. I was thinking in the direction of requiring a password to open the sansa on a PC similar to the U3 flash-disks.

Maybe there even is a way of implementing this myself. I would appreciate any feedback of programmers who could make such a feature.