jimf
I think it would be mistake to read into these texts that operators are not bothering too much about HUMS alerts. The nature of the HUMS beast is that it is uses external accelerometers to monitor and extract vibration signatures for individual shafts, gears and bearings within the tranmission (ie it is non-invasive) all in a pretty nasty environment of heat, dirt, salt, oil and grime not to mention overall flight vibration (not to be confused with transmisison vibration).
The net result is a relatively high false alarm rate, or at least a need to be circumspect in not jumping in with both feet when the HUMS squeaks, without thinking carefully about it.
The false alarm rate is much lower these days - as I mentioned earlier, HUMS is an evolving science (or maybe an art!). It is not perfect, but I get nervous when it is implied that "it don't work so it ain't worth having" because whilst far from perfect, it is still a quantum step forward in flight safety.
In our company we have a couple of very experienced engineers whose sole job is to keep tabs on the HUMS systems, even though these are supposed to be "user friendly" to line engineers, and we do take any such trends very seriously, but at the end of the day a qualitative judgement has to be made as to whether it is a significant issue or not. 99% of the time we get this right, and it doesn't make the papers. Just occasionally it goes wrong and then does make the papers!