It is a hot beverage that is often served hot in many places. There is inherent danger when ordering and drinking such a substance. Due diligence and care should be made to keep yourself safe, and it is preposterous to say it was their fault you spilled a hot drink on yourself.
Now, McDonald's, as a corp and living in this day and age of the lawsuit for tripping in the parking lot should definitely have known to settle cheaply. However, I will always have a problem with somebody who spilled something on themselves suing another for giving it to them...