A user with a reputation of 3 (Naelin) deleted the text of my answer and substituted their own. There was an issue with my citation (it is fixed now), but deleting the text of my answer was not the solution.
Does this case highlight a flaw, or is reversion the one and only answer?
The deleted text:
The insurance data are unequivocal. In 1997, the non-profit Highway Loss Data Institute (HLDI) surveyed insurance-claims data from 73 million vehicles, to see which devices could prevent theft. Looking at cars from many different model years, across the country, the study concludes that cars with alarms "show no overall reduction in theft losses" compared to cars without alarms.
The added text:
There are a variety of antitheft and tracking systems on the market with costs ranging from basic audible alarms costing $50 to sophisticated tracking systems with $30 monthly fees. Unfortunately, the effectiveness of many of these devices is questionable. The sensitivity of audible alarms to touch or movement, for example, provokes a “boy who cried wolf” reaction. When a car alarm goes off, people tend not to react because the alarms activate so frequently for reasons other than actual theft. HLDI studies show no overall reduction in theft losses for vehicles with such alarms.