As part of the crash avoidance for 0000040 null checks were added to code that really shouldn't need null checks. At some point this should be investigated in more depth to figure out why clients are trying to perform operations on groups that are either removed from the scene or haven't yet been added to a scene.

If we can confirm that the reason the group has no scene is because the group has been removed and not because it hasn't been fully constructed yet we can keep the null check and remove the assertions.