I remember this when it happened. Wasn't Kahl part of a group? I remember that he wasn't paying his taxes, that's what the stories on TV said, not sure about not owing so not filing. I never heard that before. But I do know he and his group were advocating that others not pay their taxes.
There was a rancher just west of where I grew up that was part of some radical group. He supported Kahl. He owed taxes, and they took his ranch. He had made statements of over his dead body, so they went in with a show of force, busted a glass bottle of ketchup over his head lol. I went to school with his kids, and were on the same sports teams. He used to write long letters to editor of the local paper about the monetary system. Bottom line he didn't believe in money. He was a strange dude. I rode back with him, his wife and two kids from a wrestling tournament in Wisconsin. What little I gathered from that trip was he didn't like any laws that restricted what he wanted to do. He couldn't drive since they took his license, and complained about that and basically any laws of the HWY, including licenses, registrations, etc.... He had some strange views. His kids turned out OK though.