Budget, inertia can be pretty strong in police forces.
I’ll give you a Canadian anecdote, and its not exactly your hypothetical situation, but hopefully it covers the idea.
I used to work in a bar about 10 years ago, and driving home, would occasionally encounter drunk drivers.
Dutifully I would phone 911 on my cell phone. After specifying “require police”, “drunk driver” and “I’m following them”, the dispatcher would ask my name, home address and home phone number. They want to know who you are.
And then they would phone my house at 4am to confirm that I live there, waking everyone up, possibly scaring them, but more importantly, nobody at home would have any idea what is going on, nor would they appreciate such a call.
If they were then satisfied as to my identity, and resources permitted, a car would be dispatched. Presumably they also ran my name as part of their character reference.
More often than not, especially on a Saturday before dawn, the process never resulted in any police showing up. They would have found domestic fights and their own drunk drivers.
So that seemed to be standard protocol for responding to someone causing imminent danger through reckless driving. The RCMP are noted for being pretty professional too. They would have come if they could.
Random J. Pothead is going to experience much the same process. Think he will enjoy that scrutiny? If he has so much as a whisper against his name, or no fixed address, or wont provide one, the police are going to toss his claims; especially since they probably have more pressing matters to attend.