Some gates are designed to keep people in; others are designed to keep people out. In Never Let Me Go, sometimes it's hard to tell the difference. Fences pop up all over the novel, but it's not always clear if these gates
(a) protect the clones from the outside world
(b) keep the clones from leaving, or
(c) all the above.
When they're younger, Kathy and her friends can't leave Hailsham's safe bubble world. So there the gates go with option C. Yet as they get older, Kathy and her chums gain more freedom. They can drive, take road trips, and have mini-adventures. But even with the extra freedom, Kathy and her friends learn that sometimes there are barriers that you just can't see.