Can an ESTA be activated at the Canadian border if travelling by car or do you have to be flown into the country for it to be activated?
Also, I know there is a clause that says "there should be a reasonable amount of time between visits so that the CBP Officer does not think you are trying to live here. There is no set requirement for how long you must wait between visits." If i was re-entering the states the same day I left, and with a flight booked for England 4 days later, would you think a reasonable CBP officer would let me through?