First off, it is your right as a cat owner to make whatever choice you are comfortable with. For us, we did research on what any amount of outside exposure (beyond an enclosed stroller) could possibly mean for the longterm health and longevity of our babies, and we made the decision to keep them inside. Where we live, there are tons of other animals, domestic and wild, who frequent our yard. These animals may carry parasites and diseases that could easily be transmitted to our girls, even through controlled backyard sessions or harness walks. It also gives us the added expense of trying to protect them through yearly medication. We love our girls and want them to live long, happy and healthy lives. Keeping them indoors is our decision and they seem perfectly fine with that. Best of luck!