But if they are going to be practical, they'll choose everyday not to turn into a scam because they won't earn money anymore if they'll run off with the huge amount of money deposited by their customers, it's just one time big time but running a gambling site effectively in the long run is much better, much money they could earn while maintaining their reputation in gambling industry (online).
Also, big gambling sites won't be that fishy when they required KYC before or when their customer are cashing out their money, unless it's a newly made gambling site with a poor UI, then that's when you should be careful and have a second thought about depositing money on it.
With new sites, you always need to be careful, it is better to wait a while for people's feedback on the work of these sites to appear and only after that start deposite your funds there. I see, following the example of my city, bookmaker offices have closed almost everything that was known to me. I think there is no need for them now, since now you can bet on any event online without any problems, without leaving your home, just from your smartphone, it is very convenient. And there are many sites out there that value their reputation and work great, with good support.