They can be blackmailed but can't be gagged as any request for a person's data (including access to it) from a Swiss company MUST go through Swiss court. And even gag orders can't compel someone to break the law. Same situation as three letter agencies requesting EU data from Microsofts' datacenter in Ireland, which whilst it is an American company (and thus they are obliged to deliver by law) is illegal under EU and Irish law, thus preventing Microsoft from giving said data without breaking the law.