So, whenever you walk a jump course, either XC or showjumping, you need to stop looking at the jumps as a human. You must try to see things the way a horse instinctively sees them.
That brush box is something many horses will look twice at. Why? Because horses know that dangerous critters live in brush. They will instinctively worry about any jump that has brush in it.
There are many examples of jumps that purposely incorporate known "buggers" in them as an effort to cause refusals. If riders don't learn to see jumps AS HORSES SEE THEM, they will fail to recognize these traps and rack up the penalties.
When I walk XC courses with students, much of out discussion is not what we, as humans, see...but what is the horse seeing? Most of my students don't fall into these jump traps.