There appears to be a border around the field, which is why there are 2 parts to the trip gate. With a raised border (about 2 inches it looks like) there could be something they fill the field with. This could possibly be water, or they might do corn kernels (see the first game). I thought they were going to save the remake of the original game for the 20th anniversary (next year), but I might be wrong. They could also have the field empty and fill it as we play.
With the other hint, those could possibly be rails that we have on our bot that we use to move, and we don't even use wheels this year.
As a side note, the first game hint could be we attach our bot to one end of one of the poles with our teammate beside us, and we have a tug of war with the other team
EDIT: I don't know about any other competitions, but the GTA regional is held at the Hershey Centre, which is a hockey arena, so ice is definitely not out of the question.