I don't live in a "Gated" Community but we do look out for each other. The moment any of us see a suspicious vehicle or person in the area we call the police. This kind of vigilance makes our area safe. From what I can see most gated communities are in area that aren't so good so its a way of keeping out the undesirables but it still doesn't stop crime happening there.
The gated communities are not what they used to be. Even in these isolated sections of the country you would think you are safe but you aren't, criminals still find their way in. Gated communities now have to pay for at least two security guards to be monitoring who goes in and out.