According to Fire Engineering magazine, one reason for the slow response to the Great Chicago Fire of 1871 was that fire alarms were kept locked to prevent false alarms:

Q: Prior to 1870, street corner fire alarm pull boxes were kept locked. Why were they kept locked and how did a person gain access to 'pull the box?'

A: They were kept locked due to false alarms. Nearby shopkeepers or beat cops carried the keys.

Here's Robert Cromie, writing in The Great Chicago Fire (Thomas Nelson: 1994), page 33:

William Lee, the O'Leary's neighbor, rushed into Goll's drugstore, and gasped out a request for the key to the alarm box. The new boxes were attached to the walls of stores or other convenient locations. To prevent false alarms and crank calls, the boxes were locked, and the keys given to trustworthy citizens nearby.

What happened when Lee made his request is not clear. Only one fact emerges from the confusion: No alarm was registered from any box in the vicinity of the fire until it was too late to do any good.

Apparently, Lee said that Goll refused to give him the key because he'd already seen a fire engine go past; Goll said he actually did pull the alarm, twice, but if so it must not have worked.

(There's more about what sounds like a really bad communications failure, but it's a little too hard for me to read on the Amazon website.)

Here's more:

But did you know that the fire burned for over half an hour before an alarm was ever sounded? Alarm boxes were actually kept locked in those days, to prevent false alarms!

When the first alarm box was finally opened and the lever pulled, the alarm somehow did not get through. The fire dispatcher was playing a guitar for a couple of girls at the time and he kept on serenely strumming, completely unawares. After the fire had been growing and blazing for nearly an hour a watchman screamed at the dispatcher to sound an alarm, which he did, and the first three engines, two hose wagons, and two hook and ladders were sent out -- but in the wrong direction!

At first the dispatcher refused to sound another alarm, hoping to avoid further confusion.

Compare this with a proposed law in New York City that will require people to get a license before they can buy chemical, biological, or radiological attack detectors:

The legislation — which was proposed by the Bloomberg administration and would be the first of its kind in the nation — would empower the police commissioner to decide whether to grant a free five-year permit to individuals and companies seeking to "possess or deploy such detectors." Common smoke alarms and carbon monoxide detectors would not be covered by the law, the Police Department said. Violations of the law would be considered a misdemeanor.

Why does the administration think such a law is necessary? Richard A. Falkenrath, the Police Department’s deputy commissioner for counterterrorism, told the Council’s Public Safety Committee at a hearing today, "Our mutual goal is to prevent false alarms and unnecessary public concern by making sure that we know where these detectors are located and that they conform to standards of quality and reliability."

The law would also require anyone using such a detector -- regardless of whether they have obtained the required permit -- to notify the Police Department if the detector alerted them to a biological, chemical or radiological agent. “In this way, emergency response personnel will be able to assess threats and take appropriate action based on the maximum information available,” Dr. Falkenrath said.

False positives are a problem with any detection system, and certainly putting Geiger counters in the hands of everyone will mean a lot of amateurs calling false alarms into the police. But the way to handle that isn't to ban Geiger counters. (Just as the way to deal with false fire alarms 100 yeras ago wasn't to lock the alarm boxes.) The way to deal with it is by 1) putting a system in place to quickly separate the real alarms from the false alarms, and 2) prosecuting those who maliciously sound false alarms.