Sports bettors don't get much in the way of comps. They can get a free drink at most places with a $10 bet. The ticket writer will give up a drink ticket that can be taken to the bar -- though often you have to ask for one. The Mirage used to give a comp to the California Pizza Kitchen if you made a bet of $5,000 or higher. Circus Circus gives 1% in comps back that you can use at the Steakhouse. There aren't too many benefits for sports bettors.
As for sports-betting whales, yes, some sports bettors make whale-sized bets. Over the years, there have been a few million-dollar bets on the Super Bowl and the like. The problem is finding a sports book that will fade (handle) that kind of action. An occasional high-profile sports bet might be good for a casino that's looking for some publicity, but day in and day out, the biggest sports bettors and syndicates often have to resort to subterfuge, such as messenger betting, to get the big money down on games. Unlike the pit, most sports books don't relish accepting huge action, which unbalances their books.
Remember, sports bettors aren't gambling against the house; they're playing against bettors on the other side. All the book wants to do is balance the action so that the losers pay off the winners, while the casino rakes its vig off every bet.
Anyone that might skew the book's books quickly becomes persona non grata, which is why 1) the whales tend to remain anonymous and 2) they don't get much in comps.
For a fascinating look in the world of sports-betting whales, read the Huntington Press book Gambling Wizards -- Conversations with the World's Greatest Gamblers.
