Had more than a couple clients kill elk after the horses or mules alerted us to their presence. Literally would tell my clients "If your horse snaps its head up or becomes fixated on something use its ears like gun sites...more than likely there is an animal standing there watching us." We had horses alert us to elk, moose, bears, people, etc across the drainage from us over 1/2 mile away.
There are also literal search and rescue horses used for scent tracking.
not disputing what the warden said but your or his reasoning on not aiding in other means is completely false.