A requirement of racing with DBSC and any Laser Association event is that you have Public Liability insurance. It's prudent at all times, but especially for DBSC sailors given how crowded the harbour gets and the potential for collisions. You might also want comprehensive coverage for your boat, but that's your call.
YNSW has a recommended policy, and splits the commissions with DBSC. The good news is its both cheap ($50 for $10m PL coverage) and easy (on line application).