Hi I just got a black Macbook (my first!) and I have two questions regarding the build quality: 1) Is the black Macbook safe to pick up one-handed? Example: when the Macbook is closed in my backpack, can I grip it with one hand? Will the screen flex? 2) Will the screen touch the keyboard when closed and I pick it up one-handed? I noticed there was a piece of black cloth that came with out-of-the-box along with the Install DVDs and accessories. Does anyone put this cloth between the screen and keyboard?