Tugger, first let me say that I am not defending the sale of these types of monitors. I far and above believe in having employees who treat their employer's equipment as well as they would treat their own things, and if they don't, then either they need some "Special High Intensity Training" or to be shown the door in a manner that everyone knows they are no longer with the company with no further explanation needed or forthcoming.
IF the customer wants or doesn't want an "impact monitor" the decision should be made on reasons that are as true and accurate as possible.
All the incidents tugger suggests would all be items that a _properly_ installed and adjusted unit would be set to ignore, these scenario are the reason there are adjustments to how many Gs. not every location is going to be a smooth floor, nor should every forklift be allowed to go over the railroad tracks. These incidents are examples of an improperly installed and adjusted impact sensor, not of reasons to not purchase an impact sensor.
MY main reason not to purchase an impact sensor, if they were _proven_ to improve safety, they would be installed as standard (not an option) like operator presence and restraint systems are now.
There is no way to mechanically remove good training and management from a material handing situation.