It's fairly obvious and common sense that when CASA comes through and audits your aircraft's MRs (or your fleets MRs) that if there are ZERO (or almost ZERO) defects. Or defects only ever found at the end of a days operations at home base then something is suss.
Particularly in commercial ops with a handful of aircraft, it's not difficult to discern a pattern that would be worth investigating even if there was no similar aircraft to compare them to.