I was going to buy it for 2 different people for christmas but both declined over privacy concerns as they read in the news they are being used in sweeping investigations. Given the number of wrongful accusations that litter history and the general trend away from any regard for privacy among security agencies this is a very legitimate concern, even for regular folks like my parents.
They can try saying "No", then the government will just get a court order to force them to do it. They don't really have a choice in the end – the only choice they have is whether they make it easy for the government ("you want our data? here have it!") or slightly harder ("I'll need to see a warrant first..." "No problem, we are going to the magistrate right now to get one...")
They will still have clues about the state and the city and the IP address of the person. It's enough to do whatever research they may want to do with aggregate data. It's not good enough to sell this data to insurance companies and advertisers.