We get about 3-4 of these a day, roughly 1 per thousand accounts. It has gotten to the point were you have to review them, to live up to your end of the law.
Doesn't the law provide for remuneration ? Something similar has started to happen in Denmark. But the large ISP's have said "Sure we'll, find the information for you - if you have a warrant. We charge x amounts pr hour to do this" - of course "the other side" are annoyed and think the ISPs should help them for free. But the ISP's say they can't they would loose money on doing work for free. And the law backs them on this.