Not only does government abuse everything eventually, but we're talking about the government abusing our privacy rights with today's technology. What's it going to be like when we have widespread use of molecular and nanotechnology? Are people still going to say, "If you don't have anything to hide, you shouldn't worry?"
It's going to be the same battles we have fought for the last 200+ years. Firearm owners have fought for decades to keep their information from being placed into a database.
The price of freedom is eternal vigilence. Politics is a game that has no end.