A few years back the closest GW started doing this for awhile, but they stopped. I don't have a problem with it.
I also have no interest in buying any of them. If they want to charge ebay/RS store prices, fine. But grade them properly, and either set up an audition table or offer refunds if they play like crap. IMO.
I actually came across a great sorting story related to this a few weeks back.
There's an out of the way thrift I go to from time to time. I've snagged some choice jazz there a bunch of times. And I know they don't sort for profit or 'special' customers. I forget the title, but the cashier mentioned how great it was because he had it on the store's stereo a day or two before and put it back.
Anyway, the last time I was there they were sorting vinyl into genres, and artists with a huge presence. Yeah, they actually had separate shelves for Xmas albums, religious albums, and for the like of Nana Mouskouri.
Of course the blues section was full of James Last, so they might need a little educating on the genre thing, lol.