Generally speaking:

Hard to find the fastest line = good design
Hard to find the course = poor design

For local events, a course that is easy to follow is most important. You can toss some tricks in there like false apexes or misplaced apexes to keep people on their toes... the good drivers will spot the proper line right away... but a particularly tasty false apex will still often suck them in!

But, striving to make a course "hard to follow" is not the way to go, in my opinion. Go for "easy to follow, but hard to drive fast".