Assuming a car with a reasonably sized battery (Bolt, Model 3), you rarely are going to arrive "empty" at home. And if thats the case, of course you can charge

Assuming a car with a reasonably sized battery (Bolt, Model 3), you rarely are going to arrive "empty" at home. And if thats the case, of course you can charge immediately. But not every car owner has to do it, most are going to wait for the cheaper night rates. So there is a good chance of the grid not collapsing.