Are castles worth the points?

[Saber Cherry]

sachmo said:
Listen, lad. I built this kingdom up from nothing. When I started here, all there was was swamp. Other kings said I was daft to build a castle on a swamp, but I built it all the same, just to show 'em. It sank into the swamp. So, I built a second one. That sank into the swamp. So, I built a third one. That burned down, fell over, then sank into the swamp, but the fourth one... stayed up! And that's what you're gonna get, lad: the strongest castle in these islands.

:

So you're saying, that some types of terrain should have a "Castle Sinking Percent"? Actually, a random "Your castle sank into the swamp!" event would be pretty dang funny (in swamp provinces only, of course!)