I've never seen anybody get kicked out of a judge's meeting, and I don't know what the rationale would be for closing them to students. For the most part, the Judge's Meetings I've been to closely track the power-point presentation that's on the AMTA website. In most judge's meetings I was at, the judges were given a very general outline of the case -- it's a sentencing hearing, the rules of evidence fully apply, and I THINK the Alford Plea was also mentioned, but I could be wrong.
Unfortunately, something could be hammered and hammered at the Judge's Meeting (Score as you go!), and the judges will still make mistakes if they aren't listening, didn't register it, etc . . . . As far as what the judges are coming into the round knowing, the safest assumption would be tha they know absolutely NOTHING.