If you can make power usage unexpectedly go up by more than ~10% within a minute, most power grids will fail.
I'm struggling to think of any companies who could do that though... Someone with malicious access to teslas servers couldn't even do that... For example, instruct all plugged in tesla cars to start charging all at once. Assume 400k tesla cars are plugged in overnight, with an average 10kw charge ability. That means tesla could add 4 gigawatts to the grid demand instantly, which is only 0.4% of the USA's ~1TW generation capacity.