Facebook apparently owns Onavo, but to answer your question more generally, liability is probably very low. In my experience, contracts that license or protect

Facebook apparently owns Onavo, but to answer your question more generally, liability is probably very low. In my experience, contracts that license or protect proprietary, confidential, or non-public data often have an explicit exception for following lawful government orders. Which makes sense, because in general, private contracts can't overrule the law. Even if the contract did not have an explicit carve-out in the language, it's hard to believe a lawsuit would succeed. Companies and people have to follow the law, even if they don't like it. That said, companies are free to choose who they will do business with, so a data provider could always decide a certain customer is too risky for future deals. I wouldn't necessarily call that liability, though.