In Australia at least, there are regulations against installing power cabling that goes between premises (unless you're a power company, of course).

I suppose that it's a good idea to take precautions against accidentally running multiple AC devices in the same room that might be connected to very different branches of the AC distribution network. An AC connection is not the internet, where you can safely make any independent topology change as long as you set up the right routing metrics.

Yep, they're so strict that the National Broadband Network was worried that simply powering distribution point units for Fibre-to-the-Curb internet would break those rules.

Same in California. The rule is that the cabling can't cross a street. So actually you could provide power to neighbors within in the block but not the next one.

We're not even allowed to run cable between two adjacent properties owned by the same company. (A former employer of mine got around this with a "temporary" 3-phase cable going between the two, but it was regarded as a bit dubious.)

In many places the streets form a grid, it's true. You would possibly have only a dozen homes that could be connected. In other places, the streets are arranged as a tree with cul-de-sacs as the leaves. An island of acreage could emerge in such developments where you could visit dozens of homes without crossing a street.

So you would need wireless transmission. Hmm, the spectrum is regulated, but there are bands with more freedom...