Check their terms
https://betbolt.com/terms there are scenarios that they would ask their gamblers a KYC? so there's no zero KYC thing here after all.
Also how they can implement their Anti fraud and AML policy? So even if gamblers here didn't required to submit their KYC details still there are factors that can trigger for them to provide this matter. That's why its good that people is aware on this and don't play lame around believing that the casino won't ask KYC to them.
They don't advertise their casino as no-KYC casino and it's acceptable if they have some terms in ToS that they can request users KYC in special cases. I believe you know that some casinos claim to be no-KYC casinos, and advertise their casinos like this, but in fact they have terms about KYC.
If a casino detects suspicious activities from a user, they can ask KYC. It can be a big win or some big wins and big withdrawals, and it can also be suspicious activities look like money laundering for example, deposit your money and withdraw it from the casino shortly. This triggers their AML tool because this action is like using their casino for money laundering, like a mixer.
Betbolt can asnwer you better with your question.