Objects attached to the head will behave differently in stereo. If you want the separation to be computed similar to objects added to viz.WORLD, then you can link the object to the viewpoint instead. Here is some sample code:
Code:
import viz
viz.go(viz.ANAGLYPHIC)
viz.MainView.setPosition(0,0,0)
leftNode = viz.add('ball.wrl',pos=(-1,0,5))
rightNode = viz.add('ball.wrl')
viewLink = viz.link(viz.MainView,rightNode)
viewLink.preTrans([1,0,5])