Real Security Cameras Don't Always Work Either.
My neighbor had his house broken into several months ago. The thing is we live on a busy street with lots of traffic so there is plenty of opportunity for people to be seen. He kept a motorcycle and a grill and some typical porch stuff behind his house where his driveway is. The thieves (a mother and teenager) drove up in a van, got out looked up on the porch then took some patio stuff and a grill. His wife and dog were in the house at the time, and neither one of them heard the crooks.
The thing is he had a security camera, a real one not a fake security camera and he captured the thieves on tape. Unfortunately due to the angle they couldn't see the tag number of the van. My neighbor had a friend at a local T.V. station who put the film on the news. Unfortunately they haven't been caught yet, but the van had been a suspect in other burglaries in the area.
The point is, there is no single security measure that can help for every situation. Being aware and knowing who should and shouldn't be in your neighborhood is one thing you can do for free. Don't get a false sense of security because you think you can't be broken into. Use fake security cameras or real cameras if you must, but don't think that will always deter thieves, it didn't in my neighbors case.