Obviously, there will a hard verification for that. Casinos can't just be deceived by some fake papers or documents. These businesses are operated by big businessmen so expect that there's a professional approach for anything.
As if casinos will just allow a customer to enter their premises just by saying "I'm vaccinated".
In other parts of the globe, there are regions already that allow the non-wearing of facemasks just like Israel because most of their people are now vaccinated. That's why wearing face mask or any protection will now be based on us if we still want to wear it or not in the public.