Are these people too stupid to go out to their power panel and OPEN THE SWITCH that connects their home to the grid??? At which point the solar system is INDEPENDENT and "should" be capable of providing power to the home (at least partially).
If this capability isn't available (I can't see how it would not be), then the installers of said systems are due for a LOT of lawsuits.
Unfortunately it's not just a switch as most grid tie inverters have a protective circuit that is integral with the system. It can't be bypassed as the parameters are burned into the eprom or at very least set by software that the end user has no access to. Likewise, no "switches" it's all solid state. The inverter will look for a narrow band of voltage coming in from the grid which by itself would be easy to overcome. The hard part is frequency. The system also looks for a perfect sine wave of 60 cycles per second, give or take maybe .05 hertz. If an outside power source is making 59.94 hertz or 60.06 hertz it locks down the system. Not many generators are that precise. Also there is the problem of what happens when say 42 panels start feeding back into a 600 watt "pilot" generator at, say 10,000 watts. I don't pretend to know the answer to the last one.
If there are any electrical gurus out there that know how to get past those hurdles, especially the frequency one, please feel free to jump right in.