Wow - I take off for a few weeks and I miss out on all of this. I didn't even see anything on the news about this - pretty weird.
As far as warrants go - once it is issued, and once they show it to you at the door, there is no stopping. At that point you can review the paper, heck you can start reading the warrent as they're packing everything up in your house 😉 Calling a lawyer can and should be done, but it won't stop the initial search and seisure.
Taking all the machines as they did was overboard. As others had stated, I don't know anyone who has a contengency plan for something like this, and it pretty much spells death for a hosting company overnight. While backups may be made of the servers, and even if they're at a different location, the warrent likely would include backup equipment and if not already stated, would reference the backup location by address and that equipment would be seized also.
Pretty amazing stuff. I need to go through the followup articles so I can hear how this plays out!