No matter how you slice it, the best way is to cut them off at the trade routes and basically ignore them publically while keeping a close eye on them (hey, sometimes they do actually deliver on the craziness).

It's really a lot like Planktin in Spongebob. All talk, no actual effective plans to steal the Krabby Patty.

Damn, this is the exact moment I fully realize that being the parent of a 3 year old has changed me...