No one has all of the answers, and most people are learning as they go along. In the mini-sims I always tried to gather up as much information as I can and make a sort of informed “gut” decision. It is always good to communicate with the people you are working with as they may know something that you do not. For example Mini-sim 2 had two possible outcomes, you could have taken a risky route but have been able to complete it on time, or take longer but be more accurate. To answer your question, I do not believe it is very good to have tunnel vision. There is usually always more than one way to solve a problem, and having tunnel vision will only limit your ability to see other options. And yes a fail safe is always a good option. Could you elaborate more on what you mean by additional cost? Because the way I perceive it is a back up plan; which never hurts to have.