Advanced knowledge of what happens in a game

Ive noticed recently that some people on football markets will have advanced knowledge of what happens in a game. I tried lining up bookmakers and see when they suspend their odds vs someone takes a price. And consistently they will take an odds for a small amount right before the market is suspended.

Obviously they cant get away with this on bookmakers, but here's my question: Do you have to sit in the arena for this to work or do they rely on some unfiltered odds information from services. Since this happens systematically I have a hard time believing they are in the arenas for all of these games. But what service provides raw odds changes that is that much faster?

Very technical question, I know, but Id appreciate any help.
Also btw Im assuming this is why there are no coverage on markets like the NHL that do not suspend when a goal is scored.