Could be in any context. I do it a little on UFC fights but that’s a relatively low amount and I can afford I to lose any time I do. It seems like it’s becoming a really wide spread problem though, at least in the US. At the same time I don’t see why it should be illegal. Granted I also don’t think any drug should be illegal.
That’s a common misconception. Sports gambling is exactly like casino games. Odds are skewed in exactly the same fashion in the house’s favor, the payout is lower than the win probability. In the long run, the house always wins.
Also, as the industry relies heavily nowadays on trading where any event can alter the odds in real time, I guess the only way to cheat the system would be akin to insider trading.
https://en.wikipedia.org/wiki/Mathematics_of_bookmaking