If you’d like to provide ATC service, and further more to promote it, you should be prepared to offer all services as best as possible. If traffic and weather allow for pattern work, it should not be denied. While there are no formal rules on the training server for ATC, and you can do what you’d like, I strongly believe that not allowing patterns (without proper reasons) is a disservice to the pilots who enter your airspace. In the event that the pattern becomes full, you have commands at your disposal to keep more planes from entering the pattern. But until the pattern is full, traffic builds, or weather deteriorated, why not provide proper ATC service?