This forum has a pretty large hard-on regarding telling others how to live their lives... If people don't mind paying more to live in a gated community then screw it, let them do it. It's not like the government is subsidizing it...
Here is an interesting one from Calgary.
It's a faux-island on a suburban lake. It's just a single street of million+ dollar homes, all with lake access (obviously).
If the residents were seriously concerned with security, then this is one example where the gate could be effective. I mean if they put up a real fence, and manned the gate then it would be tough to rob someone and a huge pain to just cause some regular teenage mischief.
However, I know two different people that live their and they both have told me that they couldn't care less about the security of the gate. They just liked the house, the lake access and the reduced traffic on the street.
P.S. Having hung out at one of these houses a few times, I have to say, Lakeside living is one of my goals. Nothing better on a hot summer day.