a couple of posters have mentioned already, but just to add my opinion
sports books dont work like the general populace think. Sports books open a line based on a few factors, but that line is moved as money comes in on either party. The sports book isn't 'gambling' on who wins, the sports book is trying to set a line to attract maximum value, and whatever the outcome is the book doesnt care but they want to have priced the lines and accepted money to ensure they collect a small percentage of the win on any outcome. this is known as the vig, or the vigorish.
So large books globally will tend to average towards one another. Any book which is taking too heavy action on one party (say irish betting on conor) will spread that risk across other books to maintain their risk level in accordance with their desired vig.
the book doesnt give a fuck who wins, unless they've been lazy/corrupt/stupid and taken a heavy position on a certain line.
do you motherfuckers understand.