Greetings, I've read a lot that people are buying products to protect the screen from the keyboard? What's that all about? Do you know if that's necessary in the new 12" PBs? I'll be putting my 12" in a Brain Cell (from Tom Bihn) & sticking that in my backpack, so I'm not sure how much pressure will be on the lid of the top. What are your thoughts on this? And what about products like the iSKin for notebook keyboards? Anyone use these?