The fact is, a dummy alarm box with a flashing light looks just like the real thing. That’s the hope when a householder decides to buy one of these fake alarm boxes. Even so, why would you buy a replica when you could by the real thing?
Putting myself in someone else’s shoes I would say it’s to do with trying to trick would-be burglars into believing your home has an active alarm system. If you look at photographs of the imitation alarm boxes they do look realistic, so it’s hard to tell which box is fake. That’s the whole reason for buying one, to make people believe it is a real alarm in the hope it will stop them from invading your property.
To some extent, protecting your home against intruders is a mind game. As a householder myself, I want to give burglars the impression that my house isn’t worth trying to break in to. To achieve this affect, I might position a dummy box on the outside wall where passers by can clearly see it.
Hopefully, thieves will be convinced that it is real and move on somewhere else. Of course, I’d rather they give up stealing altogether, but I think that’s unlikely.
Do they work? I believe they do, otherwise people wouldn’t buy them. DIY wireless burglar alarms are quite cheap but they still need to be installed properly, and then there’s the routine maintenance. If you don’t want to go through the hassle of installation and coping with false alarms then a dummy box might be the solution, though it isn’t guaranteed to keep intruders out.
The boxes with a flashing light add extra realism. These are powered by battery or by solar power. I live in a neighbourhood where house alarms go off once or twice a month. So far, every one has been a false alarm, and because of that, no one takes any notice of them any more. It makes me wonder if it worthwhile buying a genuine burglar alarm.
For peace on mind, I would say they are a good thing. If you worry a lot about your home when you are away, then a dummy alarm can help keep your property safe.