Disabling title bars is a common way of preserving space on small screens (on netbooks, for example). For now, user has either to create an "empty" window manager theme or switch to another window manager in order to disable title bars. Having a way to do so in a simple way by clicking a checkbox would be an improvement.
Applications can use standard mechanism to hide their decorations. One of the key roles of the Window manager is to decorate applications windows (unless they ask otherwise), so such an option is denied. You may want to write a specialized window manager for the use of small screens.
Thanks for your reply! For other users who might google this bugreport, using "maximus" can be an option.