We once came across a "quarry" uphill from a large river. It was about 3 inches deep and 50 feet in diameter of all very large flakes, some 'blocks'. we figured it was a place where they did some preliminary flaking just to make sure the piece was usable before carrying them away. Never found any evidence of a camp.
I have also inspected 2 really fantastic new "campsites" as reported by wildly enthusiastic surfacers who just couldn't understand where the finished points were..
Both turned out to be dump sites for modern knappers' debris. One site had quite a few diamond saw slabbed pieces that should have meant something to the original finders.