The street finds its own uses for draconian copyright laws, it seems. In the U.S. it recently became possible to turn an IP address and a timestamp into the complete details of the person using said address at that time, simply by filling out a 1-page form claiming that the user is violating your copyrights. Not surprisingly,
these laws are being abused; recently a porn site has issued subpoenas to an ISP to discover the identities of subscribers. It is not clear what they want with the identities, but given how the porn industry attracts operators of above-average ethical flexibility (thank the Judaeo-Christian anti-sex ethic for that), all sorts of possibilities come to mind. And where pornographers go now, investigators, psycho ex-boy/girlfriends and generic marketing weasel types will go tomorrow.
I'll bet you 100 to 1 that they want to find out the details of people who have utilised their services with stolen credit card numbers or passwords.