[quote]The family has no true desire for a wish from the Grail, but want to use the War itself to assert their dominance as a family.[/quote]

So like, that's the thing. If this family's been around for a long time and is already pretty well-established and influential, the ritual being performed in hillbilly country isn't going to be on their radar. Like I said, Kayneth in the Fourth War was like having Leonardo DiCaprio show up at your high school to star in your theater club's play, him winning Best in Show (or whatever a suitable award would be) from that won't make every other famous actor be like "wow, Leo really is the king". 

You can just make it a whim, like he was just like "I'm gonna beat up weaklings and show them how real magi do it", but it doesn't make a whole lot of sense for a family on this scale to actually have considered this war as anything beyond that, let alone having considered preparing for it. 

Magecraft's now fine, be careful of those self-curses though, there's a pretty obvious risk if you misuse them.