Unless, like me, you get an exam that isn't in the Confuser. Apart from that, it's great
Seriously, Nav is the exam for which that approach is the least applicable. The routes you are given aren't in the Confuser, so unless you can work the whizz-wheel well (and you have to be precise, because a ballpark figure isn't good enough to differentiate between the answers) you are in trouble. Also, in Nav mistakes in one question lead to mistakes in others (e.g. wrong GS means that you get the wrong ETA in the next question) and so one mistake can easily lead to three, four or five wrong answers - and you can only get 6 wrong and still pass.