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If this is the same hack that hit Los Angeles County, it is not nonsense. It took out several 911 locations. Yes this works on the iPhone. When you click the link embedded in the tweet, it activates your phone app, dials 911 and you are unable to stop the call from going through. It also disables the end call button on the phone. The kid with the tweet in the LA case, was found and took the link down. However it is still out there.
 
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