Exactly!!!specially when you hit jackpot or something closes to the prize,if I remember it right there are some topics that discussed about related issues in past I dont know if until now there are still a victim of this modus of some casino sites
My friend tells me his story when he can hit the jackpot. He hit the jackpot, but when he wants to withdraw the money, the site needs him to verify his account, but he doesn't want to send any document to that site. He gets upset knowing that he cannot withdraw the money, but on the other side, he can accept the rules. So now, he always searches the gambling website which doesn't need to do KYC so he can withdraw the win money without verifying himself. That is one example from my friend who doesn't want to verify the KYC because he thinks that the document is very important for him.
He doesn't want to send it into any gambling website.
How much was the jackpot hit by your friend? I guess it was not that big, because if it was a huge amount then I think your friend will do the KYC. If he did not send the document means that the amount is still considered as low amount for him, but if he thinks that it worth enough then I'm sure he will do it to get the money.
At the moment, most gambling sites has terms that they have the right to ask for KYC. Although it is not mandatory but it can be asked for several cases like huge win, suspected as money laundering, etc. So basically big players who usually bet big amount and have the chance to win huge should be ready for KYC.
I do not like KYC as well but if there will be a time when a gambling site ask me for KYC because I win so huge amount, I will do it to get the money but I have to make sure first that the site is reliable and trusted.