I don't see why you wouldn't respond to every call you are dispatched to. As far as an officer being on scene stating there are no injuries....what type of call would have come in to 911 stating there were injuries and then there really aren't. I can only think of a car accident where a passerby may think there were injuries and called to report. Even then, a police officer isn't in a position to make that determination if there is a need for transport or not. I am not sure how it is elsewhere, but here, a patient needs to sign off if they don't want to be transported. It is all about liability and I would rather show up to a call and have to leave without transporting, than to get called off a call by a police officer, only to find out that the person later was injured. An injury isn't always apparent immediately or to the the naked eye.
There are plenty of calls where I live, as far as fire service goes, where we get toned out to false alarms and the alarm company calls dispatch and states it was false. We still go to that location just to check it out.
That is sort of like saying that a cop shouldn't check out a 911 call, where the caller states nothing is wrong. Many times it is a kid playing on the phone or someone misdialed, but that one time it's not, will haunt you if you were the one who didn't show up.
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