I think they've been doing it for a little while, not just recently. [It had been difficult to ask anyone about it specifically because a lot of them were playing into the mystique and thus weren't all that prone to give straight answers, but that's the impression he's gotten so far.] It's possible that if people died out here, they'd sent up scavengers before that had found remains. Remember that dead town we ran into on the route to the Northern Outpost? That could've gotten them a decent amount of "surface treasures" to sell on if any of their scavengers made it there. And then we showed up and "offered" them some more.

[He'd imagine it was coincidence more than pre-existing knowledge of their arrival, since that had been before the dream even came to them. Still, it's something he has been wondering about since he realised that was where the missing items from that trip had ended up.]