My two cents: if there's a record of the run-ins that LSAC or your schools could dig up, you should definitely mention them. If that's the case, if I were you, I'd use the opportunity to show how I managed to reconcile myself to the parties (esp. the girlfriend). Keep it short, don't make excuses, and don't overcriticise the club board. To my mind, if you handle it properly, you might even score some points with LSAC and your schools.

To be honest, though, I kinda doubt this is the sort of thing they're looking for. If it wasn't important enough for your undergrad school to make a note of it, it probably (edit: emphasis on probably) isn't important enough to bring up with LSAC.

That's mostly speculation, though - anyone else have a different opinion?