Do Leading Lines work? A level design perspective

Leading lines are propagated a lot when talking about level design to a point where many treat the topic as a joke. Is this warranted or is there an applied use for leading lines? Let's take a look!

[roofkat]

I enjoy how short & to the point you kept it, nicely done Tim :)

[Baptross]

Pretty cool.
This is very useful (and utilized) when the player character is being chased so the player knows exactly where to go while keeping the sense of urgency.

[julienfrisson]

And if the player decides not to follow the guidelines in an open world what to do?