I would say that this kind of sacrifice should not be expected or demanded across national borders. Had the prince forfeited or sold the land for the safety of

I would say that this kind of sacrifice should not be expected or demanded across national borders. Had the prince forfeited or sold the land for the safety of the nation then he would agree with you. but as far as I know this is more like your uncle getting kidnapped for 4 years (human life and land are incomparable, so this makes little sense) by a different country to fight their war. Note that this sort of already happen when regions that want to/should be independent get exploited in war times.