You have to assess the situation. Much like economics class it is a graph of supply and demand. If expulsion is eminent, greater risks must be taken. If I don't have to go that bad, I can wait until a more comfortable option is available. I have stopped in a gas station before, and decided that, "no, I don't have to use the restroom" and drove further down the road. Another time, I was feeling very sick, but it was the second quarter of the Independence Bowl. So, I crapped at the Independence Bowl.
Also, the Packers are going to win this weekend.