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.
I did it a few times at local horse races that i went to watch. I bet only small amounts for the fun of it, and i think it contributed a little to the whole atmosphere of the event. So, nothing serious. The most I won was, when i made a mistake and bet on a complete outsider by error. Then that outsider won, and from the proceeds i could go and buy me a new pair of jeans.