Ofcourse any casino would try to lure the players to play more but if those two players are sane enough then they should withdraw immediately and the casino should approve it within 24 hrs at most. If not, address the problem publicly.
We are talking about big winning means big amount stake here, nobody knows if the winner are pure win or there is an exploit system causing win.
Because of that some casino apply security checking few days to make sure everything ok, too risk allowing big winning cashed out instant or even within 24 hours. We just need to be patient and see what will happened.