It wouldn't be, they're almost certainly doing something wrong on the back end. I sent identical requests on multiple IPs spaced out over some time, and each on

It wouldn't be, they're almost certainly doing something wrong on the back end. I sent identical requests on multiple IPs spaced out over some time, and each one of them returned as being "unique". Even though the e.g. UA values were in fact the same. I suspect some kind of aggressive dedupe of things that look too similar, or some such.