At least here in NYC, all the news agencies, have personel sitting at
their headquarters monitoring the first-responder's frequencies.

If something goes down, they use their two-way radio to their guys in
the field, and dispatch them to the location.

I monitor THEM too... and it's kind of funny to hear them relay the
information back and forth.. and their commentary.

The other thing, most 'stringers' carry their own portable scanners,
and rove about the city late at night, hoping to get a scoop, and good
photos of an incident.

If used repsonsibly, scanners are a TERRIFIC thing for civilians to
have.

At almost every large fire, you'lll see the "buffs" together, with
their scanners on the sidelines.

Community watch groups and civilian security patrols most use them to
help and protect their own communities.

When there's an APB out for a missing child, or car used in commission
of a crime, extra eyes and ears in the field provide a wealth of help
to our already understaffed forces.

Just don't interfere with first-responder's operations, stay low-key,
and don't ever try to be a hero. It's not really worth it.

Information is their best help right now.. so, if you see something,
say something. Call 911.

As far as specifically tracking someone RECEIVING radio frequencies,
I'm not familiar with any piece of equipment capable of doing that.

If such a device existed, I have no idea how it would differentiate
someone's AM/FM stereo, wireless router, baby monitor, coordless
phone,or garage door opener from a scanner. (Yes, I know, some of
them transmit.. and that can be detected.. I mean from the "receiving"
point of view, for example.)