If you had one, your individual choice would not prevent your particular electric service from going out, so no big deal.
It would be neat if the utilities had the ability to selectively shed car chargers, clothes dryers, and suchlike loads. I imagine they have to make the choice at a much more coarse level, like at a distribution substation.
Maybe because I'm in Texas rather than California, but AC is the absolute last thing I'd want turned off. It doesn't make sense to try to convince people to reduce AC on the hottest days compared to something like charging a car, running a water heater, etc., even though this is probably the largest demand in such a case. What percentage of consumers have signed up for this program?
Residential air conditioners are usually the largest "peaky" electrical demand and most utilities have a program where they'll give you discounts in exchange for being able to remotely turn off your air conditioner occasionally.
