We had a bad break-in this spring when we were out of the country. A burglar heaved a 4 lb rock through our  glass storm window and a multi-paned  window in our bedroom. The rock then bounced around, hitting various walls. Our glass break sensor that was located next to the window failed to send out an alarm. The intruder felt free to roam around our master bedroom taking whatever he wanted, including precious heirlooms that can never be replaced. It was not until he left that room and proceeded down the hall that our motion detector sent out an alarm. The intruder left though the same window that he came in, along with thousands of dollars worth of jewelry and cash taken from the bedroom. The burgular was safe from any detection as long as he stayed in the bedroom because of the total failure of our glass break sensor.
The alarm technician sent out from their company inspected the sensor and told us that it had not been set as sensitive as it should have been. It that is the case, why should they not be held accountable? They are the company that  sold and installed the  defective product. This sensor was replaced by them 7 years ago. In addition,two separate security professionals have also told us that the sensor had been placed on the wrong wall to be most effective. The response from a company that we had been doing business with for 26 years was to wash their hands of any monetary  responsibility for their negligence. Instead, they said that perhaps we needed extra home owner's insurance. This locally-owned company has let us down completely!!