Two examples of open endorsements
Permissible Unserviceability
Under CAR 37, a defect in, or damage to, an Australian aircraft can be approved as a PU subject to any condition(s) embodied in the approval. The aircraft still complies with the applicable type design standards and is considered airworthy.
Special Flight Permit
CASR 21.197, allows CASA or an authorised person to issue a special flight permit to a person for an aircraft, which cannot meet applicable airworthiness requirements and hence would otherwise be grounded.
http://www.casa.gov.au/mel_pu/031r03.pdf
It's all very well 601 if you are operating RPT during business hours
Its a different matter at some airstrip in the bush miles from nowhere at 6.00 am on a Sunday morning.
RPT is not on my CV. but I have had defects on bush and remote strips.