You may be right, 4runnerguy, but whether a permit is required or not, it's essential for one's own safety to check with rangers before heading out on a trail. Not only will they be aware someone is there should there be an emergency of the person gets lost, they can advise if there has been bear activity or other reason the trail is closed, or extra caution is advised. As for pepper spray, etc. - it may not be allowed to use it on wildlife who are not bears. And pepper spray won't faze a charging grizzly. Bear spray may. (Never a guarantee of safety anywhere in Yellowstone.)