Review: Mouse API step 1: sol.input and pressed/released events

I'm not sure to understand this return value usage.
From what I understand, the return value should be true if the event should stop being propagated, so returning false will call on_input() for the game, map and every menus even if we don't have to, right ?
For me the event is handled in the sense that we know at the first call none of these call are desired.
Where am I wrong ?