[EricH]

Back in the day, there was speculation that there would be water. It is possible to run an FRC robot on a soaking wet field.

However, it is logistically impossible, so it's now just a joke.

As for infinity minus infinity:
1) The origination of this hint was a suggestion that trapping Billfred in a certain field area was worth negative infinity. It isn't, it's worth a caption contest. (JVN is a caption contest and negative infinity.)
2) Depending on how you think of infinity, you could come up with zero (I have an infinite number of robots, and I give you all of them), infinity (I give you half of that number of robots), or a number (I give you all but X finite number of robots). Because there are 3 different answers to the same problem, it is not defined. (And I suppose that you could come up with similar situations to have it be negative.)