shortcut – Global service hotkeys ignored in some applications

I have defined some global hotkeys which run Automator services. These work fine everywhere except in two applications (iTerm2 and Emacs).

I would like to understand this better. Is it the case that these application grab the keyboard “harder” than others, and thus disable global shortcuts while they are in focus? Or do these shortcuts generally only function if an application doesn’t handle the keypress (i.e., in any and all applications)?