[JAH]

A field covered in fog seems like a long shot to me. A large part of the competition is watching other robots compete, along with your own. If the field was covered in fog, it would make it not only difficult for the drivers(which would be the reason for the fog, a bit more of a challenge) but the spectators wouldn't be able to see the action as easily. Fog would be cool...but, as it has happened at our school, if you put out too much fog(they were doing it for play practice), you can set off the fire alarms. That all would be neat though.