Some pro bettors actually are sitting in the stadiums and betting on their phones as the events are happening so they have an edge over the books because the tv and online livescores are getting a slight delay.
In the past, it may be possible to exploit using this method.
Nowadays, there is a delay in sports betting so that people cannot exploit delays in sportsbook.
There aren't really people sitting in the stadiums doing the bets these days. The odds for live update really fast, and its not like in a tennis game if score is 40-15 , and the first guy wins another point, then the odds wouldn't really change dramatically.
If this was the case, sports books would shut down as it could become really exploitable even for small odds.