They rightfully passed legislation banning such practices. The idea is that if casinos and bookies refuse to cap your downside, they have zero right to cap your upside.
A casino or bookmaker doesn't need to heuristically identify betting behaviour that's 'smart'. They don't need to spot evidence that could be hidden by good opsec. No need to find micro-expressions or hidden cheating gadgets. Nor to do background checks to know you've got a buddy with insider knowledge.
All they need to do is check if you're cashing out more chips than you came in with.
It's not trivial for the casino to track this against a determined adversary. If you're already thinking about "good opsec", you can get someone else to help cash out your winnings.
A buddy from out of town, or a losing regular, or a poker player who the casino doesn't care if they win. In Vegas some casinos' chips are negotiable, officially or unofficially, in other casinos.
Sports betting is the one place that "prediction markets" make the most sense. Instead of there being a house to win against, the market just skims a fee. The line is set organically by betters, not be the house targeting a profit margin, and the house has no incentive to restrict successful betters because they solely profit on flow, not losses.
You do have to be careful to avoid letting whales manipulate the perceived market. There are ways to con other gamblers with carefully timed bets.
The bigger the market the harder that is, so maybe it doesn't apply at the level of online sports betting. But organized crime could make trouble at horse tracks.
But if it's parimutuel, don't you lost more on A than you can make on B?
Are you tricking other players, or is the idea that you make lots of bets on A, and then make bets on B fast enough that the bookmaker does not have time to correct?
I used to work for a sports betting company. These people definitely exist. They are few though because they are the ones who understand that the sport/game/match/whatever is irrelevant. They bet the "odd line". They bet on the platform that screwed up and didn't adjust their line quickly enough to follow the market. They don't know baseball, or football, or tennis. They just know the numbers.
We all have the occasional friend that brags about every time he wins money at the casino. If you accompany them a few times, it’s incredible how the “always winning” story just changes.
Tony is also super smart in how he gambled. Your average degenerate is nowhere near as intelligent as Tony is.
I have a very small edge in sports betting although I don't really do any of the deep overpriced/underpriced arbitrage or any special types of bets outside of wins/loses. And it's limited to tennis, a sport I've played my entire life and have followed the pro circuit closely for 3 decades. And even then my edge is very small, and the strategy I use when I do bet doesn't make me much in total return.
I don't know of any long term profitable sports gamblers - but that makes sense because why reveal yourself and your methods if you're profitable?
By long term I mean at least 1,000 bets while still being profitable. Even more impressive if they are making a living off of it.
The only person I can think of is Picks Office on Twitter.