When you see Android's lock screen, there are still some controls available that may be used without unlocking the phone. For me (Android 2.3.3 - LG version) it's the volume control and the button for emergency calls.
Unfortunately, it has happened a number of times now that, when the phone was in my pocket, it somehow automatically started an emergency call or increased the volume. I don't know how this could happen but ...
The only solution I can imagine is to disable those controls. Is this (easily) possible? If yes, how?