An office building in California installed multiple false security cameras in their parking structure to deter crime. One evening after normal working hours a woman was assauled in the garage, to her credit she fought with the perp until she came to be in front of a "security" camera where she expected someone to come to her aid. She was brutally raped and assualted, as the camera was nothing more than a housing & an uplugged, aged camera. She was awarded in excess of $1M in the following civil trial.
For this type of need, speak with a security specialist to explain the costs, benefits, and cons of any system, and not the opinion of realtors. I would suggest a motion activated camera that is feeding to a DVR with a 10-14 day storage capacity. That way, if there is a problem, you may capture the incident on a digital format, but not incur the cost of 24/7 monitoring.
Best of luck,
Anything can be used as long as the Homeowner's Association agrees to it. Fake security cameras are not a great idea, but, I would suppose better than nothing. If you are living in the complex, you can bring up your concerns to the HOA at the next meeting....which I would suggest you do. (Please keep in mind real camera systems can be quite costly. And you need to think about who will watch them on a 24/7 basis.)