This way my question when faced with the dilemma of finding some sort of anti-theft device after having my vehicles repeatedly vandalized and stolen for the second time.
The quick answer is maybe. A thief doesn’t want to attract attention, so one is inclined to believe he’d most likely attempt to break into or steal a car without an alarm than with an alarm. But like you said, most people ignore car alarms; and a resourceful thief can bypass many anti-theft devices.
Fortunately, manufacturers have stepped up their game a bit when it comes to auto alarms. I’ve learned that today’s sophisticated models are sold bundled with options that offer additional deterrents like killing the engine when attempts are made to start the can without a key, or paging the car owner via 2-way remote whenever anyone loiters around, or attempts to move or break into their vehicle. Of course, the options you get depend on what you’re willing to pay,
In fact, being able to continuously monitor the security of my car (and having the opportunity to immediately address the problem) was the deciding factor in purchasing the particular model I selected.