For example:

while playing an audio file, with Preferences open on Display tab:

$ gconftool-2 -s /apps/totem/show_vfx -t bool true

The 'Show visual effects...' checkbox becomes checked but the controls 
below do not become sensitive, and visual effects do not begin in the main 
Totem window.

Worse, 

$ gconftool-2 -s /apps/totem/brightness -t int 65000

updates GConf but neither the Totem main window nor the preferences box
update to reflect the new value.

This type of behaviour is forbidden by the GConf documentation, I believe.

Version: Totem release 0.99.8.