I read in many comments that the everybody's thought process is the government might send an order to a company that says we need this information from you. Everybody believes the company could then seek legal council to fight an order if they think it's unjust or not in their best interest. I believe this is an incorrect assumption.
I also believe they are sending along a gag order as well. The gag order is, you can not discuss the information we want and the request for information we want with any other party. This gag order language is part of section 215 the patriot act. Those served with Section 215 orders are prohibited from disclosing the fact to anyone else. This was supposedly removed in 2006 with the reauthorization of the patriot act to allow for legal counsel in certain circumstances. (But the government does not have to tell the recipient of the order, they have that right.)
This means most companies would not seek out legal counsel, because they believe they would be violating a gag order.
But there is another caveat. The court orders are issued by a secret court using secret evidence. Since the court is secret, if the company wants to contest, they cannot because the secrecy of the court could override the rule of law if the secret court deems it so. Nor can you contest any "secret" evidence. The order is unstoppable.