My cousin, who worked in loss prevention at an electronics store and was a district manager for Blockbuster for many years, told me that the extra stickers were actually very effective in reducing theft. Since then I've been pretty casual about 'em. They're a hassle, but I can live with it.
And I couldn't care less about price stickers on cardboard slipcases. the slipcases almost always have the exact same artwork as the inner sleeve anyway!
For those who worry themselves silly about keeping those cases pristine, hear me now and believe me later: Life's too short!!!
My copy of The Flamingo Kid actually had stickers on all four sides of the case. I still haven't figured out what a sticker on the spine is supposed to do.