Hot key modifiers... why??

Thats not true. In foobar, when you make a hot key, you can choose if you want to make it global or not. If you do choose to make it global, you dont need a modifier but can still add one if you want to.

Hot Key Control Creation

You create a hot key control by using the CreateWindowEx function, specifying the HOTKEY_CLASS window class. When the function returns a handle to the hot key control, an application typically sets some rules about invalid hot key combinations and may provide a default key combination. If an application does not set any rules, the user can choose any key or key combination as a hot key. Most applications, however, do not allow the user to use a common key (for example, the letter A) as a hot key.

The following function creates a the hot key control shown in the previous illusitration. It uses the HKM_SETRULES and HKM_SETHOTKEY messages to initialize it, and returns a handle to the control. This hot key control does not allow the user to choose a hot key that is a single unmodified key, nor does it permit the user to choose only and a key. (These rules effectively prevent the user from choosing a hot key that might be entered accidentally while typing text.)

i see, thanks