Some years ago (14 ish) I went to interview for a funded PhD at Kings College. I was telephoned before I had even got home to be offered the post. On further reflection of the research detail given at interview, compounded by a health issue that could be exacerbated by the work, I turned the offer down. I was absolutely gutted, but it was the best decision for me at the time. So in this case the 2nd ranked candidate would have been offered the PhD place instead. I did go on to self-fund my own part-time research 8 years later and have just passed my viva in a completely unrelated area.