So your video title asks, "How?" My guess is that it is all pretty simple. As the guests sign the filming waiver, they are each giving up their identity, perhaps even proving it up with providing their driver licenses. From there, a crack team of hackers (basically a single 13 year old INCEL) does a deep dive into criminal records, social media, noting dog pictures, birth dates, etc., and from there a bit of a clever patter can be concocted on the spot to seem spontaneous. That's my guess. The real magic here is in how amazingly smooth the presentation is.
@@YoungManDub Absolutely, there is no way you could have found 90% of the info Derren had online back in the early 2000's. He also does this in live shows to random audience members and has an incredibly high 'hit' rate.