Locking in CP6 -- Is this a bug?

Hi

I am using CP6.0.1.240.

I have a locked slide and some locked objects (on a different slide that is not locked) in my template file which my colleagues should not modify when they review the file.

As far as I know, when I lock a slide or an object or group of objects in a slide, my colleagues should not able to unlock it and modify it. However, they are able to do it. So, is this a bug? Or am I missing something here?

Thanks in advance.

Sreekanth