Air law, regulations and licensing requirements
The two instruments you must not confuse
RPA regulation in Australia lives mainly in CASR Part 101 and its Manual of Standards, supported by advisory material and the AIP/ERSA for airspace matters. The RePL is a competency qualification held by an individual and carries endorsements for the type of RPA (e.g. multirotor, aeroplane) and weight band. The ReOC is issued to an organisation and authorises it to conduct RPA operations, carrying the obligations for procedures, training, maintenance, record-keeping and reporting. A pilot may hold a perfect RePL and still be unable to operate commercially without an operator's certificate.
Obligations worth memorising
Operate within the standard operating conditions or an approved procedure; keep competence and currency; maintain logs and records; report accidents and serious incidents to the relevant authority; hold appropriate insurance; comply with privacy and other non-aviation law. Approvals for non-standard work (beyond visual line of sight, night, above the altitude limit, near aerodromes, in controlled airspace) are separate from the licence itself - a common exam trap.
Worked example / rule of thumb
Person needs a licence, business needs a certificate, and anything unusual needs an approval. If a four-kilogram multirotor is flown for a client, the pilot needs a multirotor-endorsed RePL and the business needs an ReOC; a two-kilogram RPA flown strictly under the excluded-category conditions may need neither, but every standard operating condition still applies.
Traps
Assuming an RePL authorises any RPA anywhere; mixing RePL and ReOC; forgetting that registration and marking rules are separate from licensing; ignoring that CASA approval conditions are binding.