That's when they will start asking for documents and proof of ownership and identity from that person. Just be sure that you're the person they really are dealing with because when they start being doubtful to you, you really have to proceed what's being asked.
This is one smart way to address the possible submission of KYC. Since we are having several reputable casinos and sportsbooks already. You can easily spread your bets without worrying that your bet is too big for them. Because a lot of known casinos here even if they have gaming license, they are not requiring KYC, unless, you surpass their maximum deposit or withdrawal requirements for level 1 player. But you should also be prepared in case they ask you. So you are not caught in the middle if you happen not to be ready about it.