Windows7 intell HD graphics core i3 762MB
Broken: 2.49b, 2.69 possible in newer versions too.
Short description of error
There is a visibility bug, hard coding with python does not resolve it.
Exact steps for others to reproduce the error
Based on a (as simple as possible) attached .blend file with minimum amount of steps
copy default Cube, parent Cube.001(child) to Cube(parent)
on Cube(parent) in logic bricks; do a keyboard sensor (any key) > and (controller) >edit object_addobject (actuator) in "OB:" enter "Cube.001" without quotes.
on Cube(parent) go into edit mode and scale to a smaller size (so the added (Cube.001) object will appear bigger than Cube if spawned as visible)
exit edit mode.
On Cube.001 (child) do an Always sensor > python
in a text file to be used for the python script controller:
cont = GameLogic.getCurrentController()
own = cont.owner
send Cube.001(child) to layer 2 and keep layer 2 invisible.
run the game and press whatever key you set, the cube will be spawned but will not be visible, no matter what you try it's visibility flag will not toggle!