nikcub raises an important issue - one must consider the contract between the end customer and the service provider. The analysis doesn't end here though.

There is a lot of additional complexity -- not only are there other contracts in play (e.g. contract between Megaupload and Carpathia and any other contract between Goodwin and any other 3rd party impacting the data), but also the issue of whether and how the court will enforce those agreement.

The government's ability to access the data changes depending on how these agreements are interpreted/enforced.

If you want to get really pedantic, there is also the question of whether the court is appropriately exercising jurisdiction and therefore has the authority to make and enforce such a ruling.