James,
The point is that while it's legal to enter a MATZ without permission, in many cases it's totally stupid, if you know or suspect it's active. But if, for instance, you know Shawbury has nothing going on after 5pm or at weekends - which is indeed the case - then you call up, and receiving no reply, fly straight through. As I did for several years when I was based at Sleap. That's why there's no one right answer.
If the exams were essay type, then asking the student what he/she would do, and why, would be an excellent question. But a right/wrong answer has to be right or wrong in all situations and circumstances.