That's a hellava party, 2 weeks is quite the get together, but it takes a bit to prospect so I could see it. I've already been planning weekends this summer to go sluicing up north. It's right below one of my climbing areas so I can climb one day then sluice the next, then be home for dinner.
You might spread the theft around casually amongst the group if you haven't already. Could be good to get the group looking down on the douche bag.