There's plenty of scientific research out there about the effects of fatigue on the faculties and the ability, or lack of, to respond in the same way as you would in a non-fatigued state whether it's sport, work, flying a plane, sitting behind a computer, etc. Blair would have been in this state.
Alison's actions were plainly in the wrong and I can't really come up with any reasons except she does come across as a bit the 'look at me' type and everything and everyone should revolve around and accommodate her and her actions.
As for the RD and some of the crazy things he's said in defence of DQing Blair well, he must be hoping to crack on to Alison.
And as for the comments above from her friends Steinberg, Stout and Skinner, please us a break, you've gotta be kidding.