@jberryhill ,
I assume you don't normally register cctlds.
The domains do not get blocked immediately. What normally happens is,
the domain gets a temporary suspension and a verification process is initiated in which the registrant needs to provide reasons for the registration of a prohibited name.
If, for example, you assure the registry (providing the necessary documentation) that 'Casino' will not have anything to do with gambling OR if your gambling activities are within what the country consider 'legitimate' use then they will un-suspend your domain and you will be free to carry on whatever it is you intended for that domain.
There are also cases where prohibited names get registered and the registration slips between gaps in the system. However, the owner is always at risk losing the domain upon some random inspection.
Now, it is important to note that, all I say regarding this issue comes from what I personally have seen through the years registering cctld domains. ie. what I have been told by registrars, registries, and various other entities.
I have never read any country's official documentation in full and rely only by what I have seen and been told personally.