A standard US dryer outlet is rated for 30 amps at 240v. For a sustained rating of 80% that's 5760 watts, which at 4 miles per kwh is 23 miles per hour, not 30.

Frankly it would take a hell of a lot to convince people to be ok with getting home, plugging their car in, and having the charge level go down instead of up. I certainly wouldn't be comfortable with it.