> Liebeck's attorneys argued that coffee should never be served hotter than 140 °F (60 °C), and that a number of other establishments served coffee at a substantially lower temperature than McDonald's. The attorneys presented evidence that coffee they had tested all over the city was served at a temperature at least 20 °F (11 °C) lower than McDonald's coffee.
Reading through wikipedia's discussion of the trial and verdict, it sounds like the case hinged entirely on the temperature of the coffee being unusually high, and not the cup design.
https://en.wikipedia.org/wiki/Liebeck_v._McDonald%27s_Restau...