I know a lots of people there live in gated communities, lots do not. When my daughter called me about Dr Sievers we both wondered (for several reasons) why they weren't in a gated community due to her occupation. Regardless of how nice this established neighborhood is, with no history of any safety problems, she came in contact daily with lots of different people at her workplace plus other organizations outside that like teen moms, etc.
Gated area or not, if someone is going to do such a thing then they'll do it somehow, someway. Dr Sievers, home alone as she was, would MAYBE? have been less vulnerable behind a gate UNLESS a perp would have access. Where we visit in Estero, residents have background checks before they can live there then visitors have to have dated passes scanned upon entering---I understand this to be typical but I'm not sure how this may vary in different communities.
Here in Ky my dermatologist (female) was murdered in 2011, in her van while leaving her office outside parking lot, on a September evening at 7pm (still daylight). A man her family had befriended & helped had become infatuated with her, made harassing calls to her & her husband over some time period. They had lots of contact with local LE, also restraining orders. The man left the state for a while, still would call her leaving messages professing his love for her, etc. Then one day he just showed up, waited for her to leave an empty parking lot, walked up to her van & shot her several times. No one saw him, no security cams anywhere AND in this parking lot there were 3 large office buildings, 1 being hers---but at the time nobody was around. They did catch him because of circumstances involved but it was twisted. IF he had not any established history with her as he did, plus no one saw this happen... he possibly could have gotten away with it with pure luck. Be aware of your surroundings, always!