Aye, I debated what to do, too.  On the plus side, this makes the integration with Formo and Kohana smooth and simple, it (arguably) helps maintain better MVC separation, and it isn't too many extra files (two per module).  On the minus side, it means that devs need to look in two places to define their forms, and that their messages could be accidentally overwritten by another module.

Now that I've added another minus (Bharat hates it!  :-) ), I'll see what I can do to change this.  By default Formo doesn't work this way, but I suspect that it's nothing a class extension or two couldn't fix.