I'm not sure how other casinos work but stake for example requires KYC upfront. Duelbits ToS just states that at any point they can KYC a withdrawal.
They'll gladly take your money and let you gamble but once it comes to cashing out they can decide to hold it until you verify?
Very shady practice from a "legitimate" casino.
It is indefensible and duelbits should no longer be recommended.
If I may interject here. How the heck requiring KYC on random basis is worst than asking KYC upfront? You can always voluntarily KYC your account the moment you finish your registration.
They doesn't take your money but rather hold until you verify your account. If you don't like to hold your money by the KYC procedure then I suggest to do it earlier before you deposit any money since you already knew that they will ask KYC at some point. They are doing this to welcome players to try first their casino without scaring them away by the upfront KYC. I preferred this way instead of doing KYC upfront since you can try first the casino using small amount and move on if you didn't like it without providing your ID upfront.