When I would shop at game stores before I had a store, one thing I swore I would never do is shrink wrap books. How can I possibly tell if I want a book if I can't see it? Most of the "shock and awe" stores, the ones with tons of inventory that seem more like time capsules than businesses, tended to shrink wrap books. Often it was because they intended to carry that book until it sold or their store closed for good. However, it turns out most stores have a pretty good reason to shrink. It's one more store practice I probably owe someone an apology over.
What I discovered fairly soon after opening my store is that a lot of RPG books will bow and warp with the weather. Eventually you're left with a sad little book that nobody wants. That book, despite how good it was, would end up in the clearance section, and no store owner wants to re-order something they just clearanced.
This is also a reason why game store owners like me prefer hard cover books (unless those warp -- AKA Mongoose). I'm often fairly oblivious to price, so whether it's a $20 softcover or a $35 hardcover matters little to me. There's even a part of my brain that would rather sell far fewer $41 Warhammer Fantasy hard covers than more $33 soft covers if I don't have to worry about them warping and becoming shelf worn.
So to fix the warpage problem, we shrink wrap the books. We've got a "machine" that does that. It's basically a roll of plastic on a roller, an arm that melts it, and a hair dryer to shrink it. Often we can shrink wrap a warped book and it will miraculously go back to normal within its sterile little plastic wrapper.
Most of the books we shrink wrap are for Pathfinder. Why? Paizo puts out a huge number of books. We carry all of them. Only 9 of those nearly 200 books are hard cover and most of those soft cover books sell, as a group, slower than your average hard cover, but fast enough that we very much want them on the shelf. This means they'll almost all eventually get shrink wrapped or suffer the scourge of warpage. The difference in the way we shrink and others shrink is that we wait until signs that a book is beginning to warp before jumping into action. A lot of softcover books sell fast enough that they don't need the shrink. If you're clever you can use that information to see our best sellers (reinforced by the fact you can read, and are therefore more likely to buy that book, since you can see it).
I go into all this because I want to dispel the thinking that we shrink wrap to prevent people from reading RPG books. In fact, it's pretty obvious to me that you're more likely to buy an RPG books if you can read it, especially a book from Paizo. While older D&D books tended to have a nugget you desperately wanted along with a bunch of schloch, the Paizo books tend to deliver the whole package. At least that's my personal opinion and my sales experience. So when we shrink wrap a book, it's done reluctantly, with the acknowledgement that this will hurt sales. It's not to keep it for posterity in the hopes it one day sells (like our shrinked AD&D books). It's also not that way to prevent shoplifting (like our shrinked Warhammer 40K books, which disappear into our Game Center). It's just one of those things we need to do to carry that line.