As you guessed, collision shapes work between objects and not the viewpoint. You can turn on viewpoint collision and disable it for certain models. The following example disables viewpoint collision with the court but not the box:
Code:
import viz
viz.go()
viz.collision(viz.ON)
court = viz.add('court.ive')
court.disable(viz.INTERSECTION)
box = viz.add('box.wrl',pos = [0,1.5,5])