The Finnish government plans a fancy car taxation system (for links, hat tip Road Pricing and Tundra Tabloids). Every vehicle would be equipped with a GPS tracking device, and people would be paying tax according to their driving history (time and location).
This is marketed as a "congestion tax" (so greenie hipsters in city centers clap their hands) and in practice, it will be used as a tax to collect money from those who have no other option (i.e. those who drive in places where there is no practical alternative). This is an overall problem of "environmental protection taxes": if the tax achieves its purpose (for instance, some emissions are reduced, as is happening with cars) the government notices that the tax revenue is decreasing, so some other, alternative tax has to be applied to the same people who are already used to paying the "environmental protection tax". The public expenses are currently only 57 % of GDP, and that is not nearly enough, as we can see because everyone is complaining about eroding services and declining tax base.
OK, so we have "congestion tax" data collected about people - where there is no congestion. The government says that the collected data will be used for taxation only, so there should be no concern about privacy. OK, so it might be used also for solving "severe crimes" (hey, who wants to help murderers?). And of course preventing "serious crimes" as well. And why not crimes in general? Don't worry about the privacy, the data will only be used for legitimate purposes.
And we definitely trust the government, don't we? They are entirely competent in protecting their own data networks, not to mention data of individual people that they are handling?