ControllerPublic_Post::actionSave calls method _setSilentEditOptions() before saving a post. So developer can insert a lot of extra actions with dw, post, thread, forum and input. Such a method would be very very useful in other similar places like ControllerPublic_Forum::actionAddThread. Otherwise developer can't insert extra actions in controller by a proper way. It's just a matter of one empty method (to be extended by devs), analog of _preSave() for DW.
Maybe it's not a bug, but critical for better development.