It's kind of like if the 911 attackers had been kicked out of the country on visa violations, no one would have known the disaster that was prevented.
There are lots of stories of people who did have a disaster who didn't have a water valve. I personally know two people, one person had to have the entire house gutted. Both had washing machine hoses blow. I can tell you that neither of these people would have had a disaster if they had the valve I do with the auto shut-off when the system is armed and water sensors under most of the "wet" locations in the house. They probably would have spilled 2 gallons of water, not the 2,000 gallons that actually happened.