Blocking/Remove Boot Camp ablities
One of the simplest methods of preventing the use of Boot Camp Assistant to install Windows on a drive is to create a Fusion Container on the drive and install macOS into this container. Normal, a Fusion Container is composed of a partition on a SSD and another partition on a HDD. Here, I intend for the Fusion Container to have both partitions on a single drive.
The Boot Camp Assistant requires very specific partitioning arrangements to exist before allowing Windows to be installed. The configuration I propose would not meet the requirements. Also, a user would not be able to change the partitioning from macOS to meets the requirements.