Possibly because resurrection is so rare, the laws of Galifar were not written with it in mind. By the law, if a noble, royalty, or member of a Dragonmarked house dies, then their heir inherits, regardless of whether the deceased is later returned to life. Suffering the death curse is proof that that person should have passed on all of their wealth and power, but possibly didn't.
I like that idea! It certainly gives it that air of intrigue that is one of the hallmarks of Eberron. That kind of thing could threaten to start up the Last War again, or split one of the Houses.