Why does it matter so much about the value of the deal?
Surely it's a private matter between the parties involved?
Fans are just that, fans.
Legally there is no obligation for them to be made aware, though some will argue morally there is.
How would posters react if they were asked to post here their weekly earnings, house value bank balance, etc.
When I'm watching an exciting speedway race on TV, the last thought I have is how much money was involved.
Frankly, it's no one else's business.