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Comment by larrys | Hacker News Reader

I think the assumption with this is that all gunshots would be crimes in process and over time and with more ubiquity that might not be the case leading to a less effective system.

I would imagine that a criminal could use a system like this to do a DOS of police presence and/or send them on a wild goose chase so they can commit a crime in another area. In other words they get police to scramble to 5th and Main and they have another team to break into a place a few miles away with a non-gunshot crime.

Also, as anyone who has experience with home or business alarm systems knows false alarms get to be a "boy who cried wolf" issue and you begin to not take them as seriously as you should.

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The false positive rate with home alarms is not the same as that of acoustic gunshot detection alarms. Your cat will routinely set off your interior motion sensor alarm; a loose door fitting will do the same to the front door.

If criminals want to use gunshot noise to scramble police presence to a specific area, they can obviously do that without gunshot detectors. The point of detectors is to make it easier to follow up on ideopathic gunshots.

You might also note that they did not give any sort of false positive rate - they mentioned how often it correctly identified gunfire, but not how often other sounds were incorrectly labeled as gunfire. Since gunfire is uncommon, even with a fairly high accuracy rate, it is still likely to wrongly identify other sounds as gunfire more often than making accurate identifications.

If you had carefully synchronised low intensity sound sources close to all detectors, you could certainly simulate a gunshot and choose where it was triangulated to by controlling the timing and intensity of the sounds emitted by your multiple sources. Such a simulation could certainly be used to trick the system into thinking that there are hundreds of simultaneous major gun fights going on - which would obviously inhibit the ability of the police to respond to a real one, with a lot less manpower than calling in so many fights.

However, it would probably be more effort than it would be worth, so it is probably more a sci-fi / crime plot than a scenario that is likely to come up often.

What's stopping people from doing the same via 911 right now?

Nothing. That's why police usually sends some patrol to the site to check things up.

If you would get a signal of multiple assault weapons firing at the same time, you would not send just one patrol.

It's not very likely. Unless someone manages to simulate gunfire accurately with a boombox or with a pipe and some layered gunpowder + lead shots.

I still think it would be far easier and more obvious to have a few friends phone in diversions. What you're describing might feature in a Batman film with a master villain!

That would only be effective if you could get all the police to go to a specific location. I don't think they typically send every single available police officer to the location of a gunshot.

"get all the police to go to a specific location"

Maybe. But I think it would depend on the particular department obviously and geography as well. You don't need all the police. You are decreasing manpower and ability to respond to other calls which can vary greatly depending on what else is going on. And this system might be installed in smaller towns with less backup resources as well.

It's not that hard to put a few timers on few automatic arms.

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