It is however worth mentioning that we have this CIOT system which is a publicly known and automated system that actually provides automated access to name and address details of any given Dutch IP address. The system is updated with ISPs' data every morning and can be queried at will. ISPs, even the most privacy-aware one (XS4ALL) do not give statistics of how often their part of the database was queried (I asked them), but it has been made public that the database had a total of 2.6 million queries over 2010 and 2.9 in 2009. That's one in six citizens' data queried for no apparent reason.
Tech details: The CIOT system is a centralized search dispatcher, that queries systems provided by individual ISPs. A government official can enter an IP there and within seconds all ISPs have been queried and one probably returns a match.