This [1] was an interesting article from a 3 years ago about Tennis "Court Siders" - people paid to transmit results of games back to betting syndicates faster than the official bookmaking results services. Kind of low-latency sports betting...
It is amusing to see integrity and sports betting in the same sentence. You created a game where people are incentivized to make bets on the next action. What do you expect? Of course people will want to gain an edge anyway possible.
Oh this is gambling. The House has to win everytime. Sorry I forgot.
For example, consider a game with evenly matched opponents. At 0-0, the server might have odds at ~1.5, with the non-server having odds at ~2.7[1]. When the score moves to 0-15, the odds might move closer to even, eg 1.9/1.9. If you're able to get information about the first point ahead of the crowd and place a bet on the non-server at 2.7 when the true "predicted outcome" is closer to 1.9, you obviously have a massive advantage.
This can also be used to bet on sets or matches, but the advantage is much smaller. Still, a better with any sort of advantage will always win over the long term.
[1] Yes, those don't add up to 100%, welcome to the vig :)