Most racquetball events in the Austin area will be self-refereed. These events will use the rules from USA Racquetball. You can also download the rules file as a PDF to keep handy on your phone.
For larger events, like the Longhorn Open, or state singles/doubles, or regional singles/doubles, then referees will be used. These referees will be players playing in the event. You will definitely want to be prepared for that experience. You can become a certified referee, completely online.
Referee Certification Program
Walk through of the registration & test start process