And even if we do know that they received such an order, what does that tell us? Does that tell us that the US government is targeting someone using iClouds? Or maybe it tells us that the US government issued a pointless order just so they can void this so called "warrant canary". It tells us very little.
Ultimately, unless corporations-as-persons have the right to speak freely about government orders it receives, we can only assume that everything transmitted through the Internet can be intercepted and given to the US government.