They do not verify their information with preexisting data, they include anything that’s submitted to them including a lot of stuff which was done for no reason other than to enter the GBWR… An example of something which isn’t very difficult to prove wrong: the person they list as the youngest king in history was 14 when he got the throne, but there have been child kings in several countries. The youngest I can think of was minus four months of age when he inherited (Alfonso XIII of Spain).
Especially if you have been drinking it.