hrmm thats odd they didnt like your off grid outlet.. if a power line is cut upstream you could feed power back up a line repair crews believe has no power.. but they should have put an automatic transfer switch which would negate this problem. Ive heard stories in past after a natural disaster people have hooked up generators to there home and did not ensure the main circuit was shutoff.. causing injury to workers trying to repair the main power lines. The only thing I can think of is they dont trust your inverter to transfer power to that outlet and not the power mains, they probably prefer there be no power output when mains are down.. You could in theory create a jumper cable to connect that outlet back to the rest of the house, and that makes them nervous.
I am sure there is all sorts of stuff on your solar panels known to the state of California to be toxic and dangerous... My windshield wiper fluid is banned in California, dont surprise me they sticker bombed your solar setup.. that would annoy me too, I despise stickers.