Lets not get into a pi$$ing contest over trust and judgement.
The business of placing an aircraft U/S is very much a matter of team work. There should be no objection to anyone rasing a work order on a jet. The important point to be addressed by the technicians, the ops staff and the aircrew is whether or not that particular work order prevents the jet from flying. We have the means to defer faults. Perhaps the amount of paperwork associated with a deferrment tends to make it difficult to implement. A system might be unserviceable (ie not available for use), but the aircraft can still be serviceable.