I don't think either of those are real concerns. The free supercharging did not overlap with homes that could be charged by cars.

Also, safe islanding devices have been very standard for at least 5-10 years. Policy 1: House watches incoming voltage, and turns off the breaker if the grid is down. House electricity + solar stay on; line to power company stays at 0V. Policy 2: Panels see that the house voltage is low, so they turn themselves off.

Policy 1 requires an electrician, but mostly just for permitting. I'd guess a good fraction of the people reading this could safely do it themselves after reading a manual. Policy 2 does not require an electrician or understanding electricity at all. It's how DIY balcony solar usually works.