As it relates to D&D, nothing. However a "hit list" is an old concept of making a list of people you would like to see harm come to. Sometimes used for intimidation for Jr. High bullies and sometimes by the kids getting picked on, just hoping fate would have a small meteor hit their tormentors.
In any event, since the very publicized school shootings in the last couple of years, the "hit list" is seen as a big indicator of whether or not a kid is about to go off the deep end and go Matrix on everybody. (And to our friends across the pond who may point to a culture of violence in the States, school gun violence keeps going down here, it's the news coverage that it gets that is increasing. But I digress...)
The bottom line is, the kid screwed up and he knows it. He's probably trying to think of anything to say that will get him out of doing time. Any good defense lawyer would advise him of the same thing.
Even though we all know it's BS, wouldn't you consider a "D&D defense" if it meant the difference between a 6 month psych evaluation and walking out a free man/woman/whatever or the alternative of a conviction on conspiracy to commit murder? That's basically the situation this kid is in.
