I'll throw something else out as an added caveat, something I ran across with a customer a few months back. A fellow contacted me complaining that his new, unfired cases seemed to have loose primer pockets and were failing to hold primers on the second loading. In speaking with him, he stated he'd bought these as bulk, from a seller over the internet; new, unfired Lapua 223 Match cases. He still had a bunch that he hadn't loaded, and I asked him to send them in for me to examine. He did, and upon opening the package, I saw that the cases didn't have they typical annealing marks on the neck/shoulder area. Otherwise, the cases did indeed appear to be new, unfired brass. I seated primers in a few, and they were most definitely loose. Especially considering how tight our primer pockets in new cases normally run. In looking at the heads and primer pockets of a few of these, I noted a very slight, but discernible marking within the primer pocket; the discoloration of where the anvil legs had been. On the case head, again under magnification, I could make out the outline of an ejector mark. These were fired cases, obviously used in a fairly hot load, cleaned and sold as "new, unfired" brass.
With the advent of stainless steel pin tumbling, you can easily turn fired cases into what appears to be new, unfired brass. Obviously, there's going to be a few out there who will try to take advantage of this, and have already done so. The customer was very understanding, and agreed with what I'd found, but the moral of the story is clear; if it seems too good to be true . . ..
Just watch who you buy from, and if you get hosed by one of these idiots, let your fellow forum members know the details.