We don't have to worry about our cats being outside. They are inside only cats. We feel that's the safe thing to do. They are rescue or pound cats. So they were to some degree outside cats before they found a home with us and have adjusted well to the inside life. Although one cat still tries to escape and manages to run out the back door very rarely, but then he always stops and stolls slowly allowing us to catch him within a few feet of the door. I think it's a fun game he plays now.