When the object in the scene becomes enabled, all objects in "observedObjects" will become Enabled/Disabled based on their SetActiveOnEnable flag. Handy for turning things on/off when starting a scene.

SetActiveOnEnable.cs

using System.Collections;
using System.Collections.Generic;
using UnityEngine;

public class SetActiveOnEnable : MonoBehaviour {

    [System.Serializable]
    public class ObservedObjects
    {
        public GameObject gameObject;
        public bool SetActiveOnEnable = false;
    }

    [SerializeField]
    ObservedObjects[] observedObjects;

    // Use this for initialization
    void OnEnable () 
    {
	foreach(var obj in observedObjects)
        {
            obj.gameObject.SetActive(obj.SetActiveOnEnable);
        }
    }
}