My mother lives in a guarded gate community (golf courses pools, community center the whole shebang), you would be surprised, they have still had a few robberies, you would think if you can pay the HOA then you would not be robbing people but it seems that is not the case as most were internal residents (at least the few they caught), then you have the gardeners etc..
Well At least they drive around 24-7 and they will call 911 if they see you passed out somewhere on the ground, also if you cannot get a hold of someone they will go knock on doors so I guess they are not totally worthless.