getVisible unexpected behaviour

[sleiN13]

I wanted to use the visibility of a object to execute (or not) certain code in a vizAction to my surprise all object returned getVisible() is True while I knew that the certain parent object where invisible. A simple test confirmed that child object don't return the correct visibility value

groupA = viz.addGroup()
groupB = viz.addGroup(parent = groupA)

groupA.visible(viz.OFF)
print groupB.getVisible()

>>> True

Is this a bug or by design and in case of the second reason is there a function that will give the result I need?