The phrase "improper purpose" means doing something wrong or unacceptable for a certain reason. It refers to using or applying something in a way that goes against its intended or appropriate use or for an ulterior motive. Full definition
For the second law firm the answer is to be alert to any indication that its legal services are being used for improper purposes. (slaw.ca)
It is sufficient if they show a bona fide claim, i.e. that they really do intend to bring an action for infringement of copyright based upon the information they obtain, and that there is no other improper purpose for seeking the identity of these persons. (slaw.ca)
identity fraud (revised Code section 403)-: - fraudulently personating another person for various improper purposes. (slaw.ca)