Be aware that these systems remain on when your powerfuse blows as long as there is sunlight. This can be a real nightmare with electrical fires.

Is that really true? I was under the impression they needed to track the phase of the grid and thus would be able to detect if a fuse is blown or the grid goes down and shut themselves off.

No, they don’t. Anti-islanding protections are mandatory on these systems. They’re safe if they’re UL 3700 certified.

These systems have seen widespread adoption in a few countries. I wonder if the scenario you describe has actually happened yet. If it was a real concern it would have by now.