In international contracts, the activity might be legal under one state but illegal under another. Which law applies? Without some reasonable language to cover it, I guess one could end up with one party to the contract between a rock and a hard place. Their legal entity in one nation bound by a contract in that nation, with their legal entity in the other nation bound by the laws of the land. I don't know the intricacies of all of this, but I suspect things could get ugly without some defined behavior built into the contract in such instances.