I know of one organisation that occasionally sends replacement engineers to one line base on the jump seat, overnight,more than likely to be on duty on arrival (working on the aircraft in which he/she flew). When questioned about this, an individual in the organisation stated that it was not economically viable to send personnel on scheduled flights if alternatives were available. I don't know if the Accountable Manager holds this view but the cause of safety is not best served in this way.
Believe me, and I can speak from a QA and hands-on perspective, the effort that goes into EASA 145/JAR 145 Human Factors training is largely wasted. Those engineers inclined to push the limit are sometimes not actively discouraged from doing so.
Throughout my career, I have also experienced QA managers' complicity in pushing the limits, often with very creative interpretations of the regulations and even company procedures. Those companies now taking this issue seriously may be those who were stung by not taking it seriously (if you understand my drift).
Again from personal experience, the pressure applied on an engineer for refusing to release an aircraft to service is huge; you may expect coercion rather than support from your superiors.