This cat sounds like she has a family and does not seem like a stray at all. Mnay people do allow their cats to go outside and return in the evening. My cousin's cat for example does not have a collar.................but she does have her claws. She's allowed to roam around in the day and she always returns in the evening and keeps coming and going in the day. I wouldn't take someone's kitty because that is so wrong and I know how much it would hurt if anyone took my pets away from me, thinking they were stray. If you do see her again, I would take her and knock on the neighbor's doors to see if she belongs to anyone. If not, take her home and post signs in the whole city, newspapers, and on the web saying "FOUND KITTY".............with the description, picture, etc. and your phone number for her owners to call you and get her back, if she still lives with them. I'm sure she has a family.