Giving away Big Mac was also taken place in Japan. But, the detail is hard for staffs in McDonald's.
A coupon for one Big Mac was delivered under a condition that ordered food isn't served within 60 seconds after ordering.
So, staffs were in a hurry, and they must have been scolded by owners of their shops in the case that they couldn't serve food within the designated time.
In my opinion, giving away must be done without forcing employees to work harder.