Covers are ripped off to prove they're not sold.
Something to do with tax relief or some such - it's not just mindless vandalism.
[url=https://en.wikipedia.org/wiki/Stripped_book]Yes I know it's a Wiki, but gotta start somewhere. and it does support what I was told somewhere at some point by someone, and I don't think it was GW specifically. Could have been a family member, as we used to be in the print industry[/url]