Should we expect companies to hold out when subpoenaed? Though I know it's often not the case, aren't the subpoenas vetted by the court issuing them? I'm certa

Should we expect companies to hold out when subpoenaed? Though I know it's often not the case, aren't the subpoenas vetted by the court issuing them? I'm certainly not a lawyer, but when I expect a company to follow laws for protection of my privacy, I also assume that they follow the laws when they go the other way.