Some cats will also 'visit' other people's homes and get fed there in addition to being fed at home. But i have never had cats that weren't allowed outside (apart from the final 2 years of my last furry friend's life- he had many health issues which led him to be underweight & somewhat delicate and under vet orders to be kept in. I used to feel bad for him so would carry him just out the door so he could get some air,  he got spoiled rotten- i loved that little dude)