The most prominent place would probably be the in-camera help itself, which currently says: "Help files not found". The text is apparently in menuhelp.c and seems easy to change. But what exactly should we write there? Currently it is
bmp_printf(FONT_CANON, 10, 20, "Help files not found");
bmp_printf(FONT_MED, 10, 150, "Magic Lantern help files could not be found. ");
bmp_printf(FONT_MED, 10, 200, "Make sure all ML files are installed to your card. ");
bmp_printf(FONT_MED, 10, 250, "See http://wiki.magiclantern.fm/install for instructions. ");
On the other hand, long-time ML users are probably so used to having no help that they will never see it. And they are exactly the ones we want.....