After having a taste of being outside a kitty will never be happy staying in. I think Boo Boo would be incredibly unhappy if you try to keep her in. They love to prowl and catch little critters. and I agree with SA that they know which battles to fight and which to avoid. Ultimately its up to you.. you want an incredibly unhappy frustrated and bored kitty or a happy and adventurous one? Yes there are inherent risks but whats life without a little adventure?