Not trying to stir it up, but very few understand Klamath Treaty rights. One needs to understand that the former Klamath Tribal reservation line runs very very close to Thompson Reservoir. Hunting by enrolled tribal members is legal per Kimbal v Callahan I, Kimbal v Callahan II, and the Ceded Lands decision (all higher court opinions). Under these higher court opinions, the tribe may hunt, fish, and trap "free of state regulation." Free of state regulation means the state has no say on how, when, or where elk or deer are taken. So, the elk legs you saw may or may not have been poached.
On a separate topic, but back on thread, my first elk was taken a little west of Thompson Res (a raghorn four point). I think that occurred in about 1989.