The stickers constitute defacement, in my book. They diminish the value of the CD to the retailer - the message is repugnant, they're large, ugly, and cover the artwork, making customers less likely to purchase a CD (the whole point of their little vendetta).

Wow; god forbid anyone might do anything to reduce the likelyhood of someone buying a crappy CD.

The stickers go outside the shrink wrap. They bring pertinant information to the attention of consumers. There's no reduction in actual value of the product. The only thing being interfered with is an (exploitative) sales process.