Yes, it's true about collectors. I collect prehistoric stones - nobody sees them but I. The objects lose their relevence when they are removed from their findspots. There's a flood of stuff being found and I prefer the decayed jewelry. I've wrecked a couple of medieval rings accidentally but have mainly conserved the items - they take ages to clean. There is yet another category and that's odd stuff being sold as metal-detected. I don't know where that comes from but it's certainly not the ground!