Well, maybe I'm reading between the lines, but pouring ketchup all over everything seems like quite the escalation. It leads me to believe there was more to the story than we're hearing.
As for the free water, Hoiball, they still have to pay the employee to give you the cup, they also have to provide and maintain the fountain that contains the water, they pay for water service, and they purchased the cup. If they gave you free water, it was at a loss to them, and they did it because they were being nice. And now they have to buy more ketchup to replace what your friend wasted (without buying) and pay the employee to clean up your friend's mess. I'm not particularly sympathetic to your friend.