So, I was participating in the discussion about keeping home streets public, which I generally support. But then I had an experience which generated this post with the idea for an opt-out option.
The key to this concept is that it is reciprocal.
If you keep your home street public, you can visit any other public home street. This would be the default setting.
If, however, you choose to make your home street private, only those with keys to your house can visit it, AND you can only visit those home streets to which you have house keys.
My hope and expectation is that most people would choose to live in an ungated community. But for those who want total privacy and prefer not to encounter or share resources with those they do not already know and trust, this would be an option. It would prevent the imbalanced situation where a person could cut off their local resources from the commons, but benefit from the commons themselves nonetheless.