From the discussion of http://mail.gnome.org/archives/gnome-accessibility-devel/2009-December/msg00007.html, children-changed signals should be emitted by atk-adaptor.
Alongside the leasing scheme the signal emission for "children-changed" has been modified. The ATK adaptor now emits children-changed signals and the client side cache uses these signals for its update.
This was introduced in commit 338e58d49bf2c1fd99591 and is available starting in the 0.1.5 release.
Children-changed signals are now sent instead of 'fake' signals in all cases.
When applications are added or removed a children-changed event is sent from the registry.
Commits that include fix:
061b2101b6b1aeadd28173c - at-spi2-core
90d1f73334703ea89a2bdd4 - pyatspi
89422700d5b03cac05ba5c7 - at-spi2-atk