The 3 "medical students" seem to think that all they need to do is discredit Eunice Stone (or perhaps all of the South while they are at it), but that really doesn't help them very much.Take Eunice out of the picture and you've got 3 students who did a very minor thing by running a toll booth (presuming that the tape reveals that the police officer is honest), followed by a rather serious action of being non-cooperative with police, followed by a rather concerning "hit" by the bomb-sniffing dog.
Combined with the different versions of stories that they've already spun, and their wanton slander on someone whom they don't know, one gradually begins to suspect that all is not copesetic with these 3 individuals.
Very strange, unenlightened behavior for alledgedly intelligent, patriotic "medical" students...