Reminds me of a time I used to be involved in a powerboat racing series. (that's a tory sport if ever you needed to name one)On the estimated visitor numbers, that's based on when the stadium gets the go ahead the whole area of the northern docks are being built on, hotels bars restaurants, the stadium is the catalyst
When they pitched to new host cities they'd make wild claims on attending crowds. They had one event in the glamorous city of Hull and the marketing blurb for the year after stated 45k people attended. The reality was the venue was next to a retail park on the banks of the Humber, on a bank holiday weekend.
Basically, the numbers are nonsense. It's the overall boost to the economy that's the big draw.