That's right and this is the example on what will happen after they win huge on a physical casino
https://www.feelingvegas.com/what-to-do-if-you-win-in-las-vegas/They are subject to undergo on more stricter KYC procedure that's why there's no sense at all saying that they should go on physical casino if they don't want KYC since this places implement more stricter rule regarding on this matter. Also they are also active taking out taxes from your winnings so with this we can really say its more better to gamble on a reputable online casino than those physical casinos due to those technicalities.
It's about huge win, but I meant you have to complete basic KYC before entering a physical casino for playing.
About advanced KYC after a huge win, it's similar to online casino too. They do this to have more information about the player, just in case government asks something from the casino business, like money laundering investigation for example. This extra KYC is like another layer used by a casino to defend their business, like whether the user has bad record, like legal issues, cheating, and money laundering too.
Generally, if you are clean, you don't have to worry about successful chance of your extra KYC, but surely it harms your privacy and anonymity more.