I've always had a concern that one day a lawyer will latch onto this when a non-ETOPS aeroplane of a type which can also be ETOPS-certified crashes. The argument will be that the operator is under a duty of care to make the flight as safe as practicable, and the fact that the ETOPS aircraft are "more carefully looked after" shows that there is a higher level of care which can practicably be applied to the non-ETOPS aeroplane. It rather counters any ALARP claims in the safety case!
PDR
It is a concern. I understand ETOPS engineering protocol, but any decent lawyer will tear strips out of this.