Mono,
yes more crews are unlikely to report a hard landing for the reasons mentioned above etc, but I think it is a company system that obligates the check,eg in yours a certain g for whatever fleet. However, if the event is on the cusp of a sampling rate, it may appear that the g loading is not so great and maybe borderline when in fact it could be a full blown weepie eye job.
That is why boeing state the final decision to report the heavy landing lies with the crew. (ie if it doesnt register but crew feel it is)
regds