Running hysterically?
Over one-third of the folks would greet them with hand guns and bazookas, one third would be running hysterically into the hills, north, south or wherever they could be 'safe' and the final third would be racing to ask for a homeworld tour.
Somehow I doubt that the seriously overweight American citizenry would be "running hysterically". At least not very far.
More likely they will be hysterically jamming the phone line calling their lawyers, as a certain character in "Independence Day" did.