Actions can only be bound to F-keys.
Keyboard shortcuts can be match to almost anything, including F-keys.
When user tries to register new keyboard shortcut that already exists, AI warns them about conflict.
But when user creates new shortcut for F-combination, already taken by action, AI says nothing.
For example, if one of my actions uses Ctrl+Shift+F2, and then I want to assign same Ctrl+Shift+F2 for 'Change case' command, AI won't notify me. Action will run, but not a command then. If I uses Ctrl+Alt+Shift+F2 for that (or any) command, it still won't run, but action will do.