My cats are indoor cats. You can imagine my surprise when I came home one day and the door was wide open and three cats were sitting on the front step just looking around. I scooped them up before they knew what was happening. My husband had answered the door and didn't close it tightly. My male cat, Louis, is completely petrified of outdoors. It is safe to let him sit outside (we supervise) as he keeps his tail touching the door. But, there is nothing scarier than a missing kitty!