I wouldn't focus on the "more than anyone on the face of the earth" part ... It's possible there are certain cases where people have lived under audio/video surveillance for extended periods. But that's not the real point the lecturer was trying to make. The takeaway point is: The level of detail to which Rasoolullaah saw's life has been documented is amazing, and possibly unprecedented in those times. The extent of which is proof in and of itself of the incredible character of the Prophet saw, and how devoted the Companions were to him as a result. Use this as yet another excuse to love the Prophet saw.