Reading that .rtf file makes me thing is the fault of DirectInput. You didn't get the whole page - you missed the following part:
Quote: "The AppIdFlag value should only be set on test computers to avoid the possibility of two applications that ship with the same file name interfering with each other's input control mappings."
Also from my reading of that, it's only because you are a developer that a new key is created each time as it creates a new one each time you compile & run - someone else using your program would only have one key for each version they have downloaded.
You can disable it for your machine by setting a registry value (attached .reg file - just download & double-click), but you should not automatically disable it for anyone using your program as other programs & games that they use may have need of it.