If I had my hands on hot cesium 137 or weapons-grade uranium, and all I wanted to do with it was make money, the US government would be the first buyer I'd go looking for. Buying it and disposing of it, thereby keeping it out of the hands of extremists and encouraging anyone else looking to sell DIY nuke supplies to bring it to them too is a much better strategy than arresting/killing me and thereby proving the extremists are the only people you want to try selling the stuff to. I'm perfectly willing to accept a response of "and that's why no one trusts you to sell their DIY nuke supplies, bfv."So the first thing is that if you have cesium 137 or weapons-grade uranium and you didn't buy it, the only people who you can sell to are extremists. It's not like Habitat for Humanity is in the nuke business.