@mulecreek, Dad shoots an elk, son doesn't have a tag, two rifles at the kill site. Warden might write a ticket depending on their mood.
It's definitely illegal in some areas.
SD- "No person possessing a firearm, including a muzzleloading firearm, or a bow and arrow may accompany a big game hunter in the field or cooperate as part of a big game hunting group unless the accompanying person possesses a big game license that is valid for the same geographic area and time of year as the licensee."
CO - ". It is illegal to hunt game birds, small-game mammals or furbearers with a centerfire rifle larger than .23 caliber during regular rifle deer and elk seasons west of I-25, without an unfilled deer or elk license for the season. A small-game, furbearer or unfilled big-game license is required." (Min caliber for big game is .24)