Locking of Series in Comic Zeal and Pages and Notebooks in ThinkBook has been a very requested feature. As a developer my instinct has been to create as tight and secure a locking mechanism as possible and because it is so much work it just hasn't happened.
Lately I've been thinking more and more about how many weaknesses any system would have, no mater how secure I tried to make it.
I’ve been using the myNoise website for about a year now. Use it more than music when working, I really recommend their rain sound.