I think this debate will rage forever. My two pennies are a personal anecdote. I had a simple little job to do at an old property, replace a cracked socket front. Being OCD, I did a few tests like Ze, PFC etc and some continuity tests as I could see some interesting work had been done. One of the L on the RFC had a break and it turned out someone had nicked it with a picture hook some years before. The picture hook had since been removed and the hole filled in and papered over. So, there was a live picture hook, no blown fuse, sticking out of the wall for a few years. When it was taken out, being an RFC, all the sockets were still working. There was no RCD at the property, and it was just chance that the picture hook never found a ground. Makes you wonder just how many RFC's have breaks in them, still undetected. If it had been a radial, it would've failed at some point either before the hook was taken out or on its removal.