My understanding is that the particular McD's had been warned already about the excessive heat of their coffess, and that the injured woman actually was burned when the coffee melted the styrofoam cup it was in.
No, she was in the drive-thru, put the cup between her legs and spilled it. The sweats she was wearing helped keep the hot coffee close to her skin.
McD's actually brewed and stored their coffee at a less than optimal temperature, although higher than most home drip coffee makers (which produce horrid coffee due to their too-low brew temp, not to mention the heater plate most of them have that turn your coffee bitter).