[EricH]

Stuff I've seen trigger one:

Portions of the field becoming detached from their mooring (usually it's a defense--rock wall, ramparts, and moat are the most common), including side panels and/or gates. It's kind of hard to score a crossing when the robot hasn't finished crossing the defense, but the defense is already damaged (as in, it's halfway across the courtyard!). That being said, a slight move probably won't trigger a field fault.

Tablets freezing--especially if it's an outerworks tablet. Even if the score is correct (thanks to manually counting and entering later), the teams can't see that they've scored a breach. On an unrelated note, teams taking their carts across the cable protector between the field and the scorers table greatly increase the risk of this happening, so don't do it if you like to not have field faults.