GameObjects that I deactivate are reactivated immediately

When I load a scene, I'm searching for particular objects and deactivating them with the following:

 GameObject[] toDeactivate = GameObject.FindGameObjectsWithTag(targetTag);
 foreach (GameObject obj in toDeactivate) {
     Debug.Log ("deactivating " + obj);
     obj.SetActive(false);
     Debug.Log ("status: " + obj.activeInHierarchy);
 }

My log output shows that, in fact, objects are being found correctly, and obj.activeInHierarchy does report false for each found and deactivated object. When I play the scene, I can see the correct objects deactivate, but they are immediately reactivated. Any ideas as to why this is happening? Any tips on rooting out the cause of this, or what is triggering the reactivation?