Harassing users is not a great idea and if you don't have the funds to pay the players, please don't allow them to gamble big or reduce the limits. Advertising millions of dollars on the line and then struggling to pay the the player shows how incompetent your casino (partner) is
They are here already since 2013 and they already collected enough BTC to be able to pay the jackpot prize and no they are not harassing players, why will they do that? Most of all they do not force anyone to gamble or to bet huge. It is your own responsibility whatever happens to you.
In case of hitting the maximum amount of the jackpot, I think the player will be asked for KYC to release the fund.
4million dollar is a huge amount so if someone is going to withdraw such huge amount, it is reasonable and understandable if the casino requires KYC.
So far there is still no single jackpot winner (even the smallest percentage) IIRC and I think it is due to the fact that most players are using auto bet and they do not really focus on the outcome number of every bet.