I have a brand new 15 inch Powerbook. I've heard issues involving the keyboard causing probalems with the screen after its been carried around for a while. Whether I go with the Booq Powersleeve 14 or the Crumpler School Hymm is a keyboard protector necessary? I notice there's a small gap when it's closed, but it seems rather flimsy, is this enough? It will be in either case and then in a backpack for the majority of each day.