For clarification, Kate stated that she was the driver and stopped and corrected herself about how much she'd been drinking and basically said she wasn't drunk at all, unlike everyone else in the car.
The point of her story was not really how big and clever it was to get drunk and have silly fights with each other. It was about how crazy and stupid but at the same time fun the crowd she was with was...and how quickly they'd gone from being strangers to knowing each other because of how intense the experience was.
I don't know how drunk Kate may have been as a driver and I deplore anyone drinking AT ALL and driving, but based on Kate's account, she wasn't drunk....a lot of people think that when they drive I know, but we only have her word on the whole story.
As for the fighting, Kate wasn't approving, just reporting, and to make a point that these guy's were nuts.