You see a lot of Desire Lines at a university campus, at least you do at mine! Of course there comes a point when whomever designs pathways (which are not just physical ones) has to reassess the purpose of the design. For example, if the point is to "keep people off the grass", then clearly it failed! Adding a fence might help, but maybe not.
I've seen folk deliberately jump pedestrian fences in the middle of busy roads. Those fences are meant to stop accidents between pedestrians and cars, but clearly theu didn't care. Or maybe they got away with that behaviour enough times that they think they're immune to consequences.
There's a roundabout near where I live near another intersection. When I used to walk Pegasus sometimes I saw a car that instead of going around the roundabout and turning left, would cut into the wrong lane and turn right instead. And then iit stopped. Later I found that the driver had tried it once too often, and drove directly into an oncoming bus (which couldn't be seen making the illegal turn). The desire line drove them on, literally.