I don't know if this is possible, but you *might* be able to only allow ppl one ip address per username. Don't know if it's possible, but it could make posting your information somewhere useless. I don't know if this is possible yet. But I know you guys can view any member's ip right? Or do they have to post to view the ip?
And also like NeoPervert said, phpBB boards have usergroups and you can customize what forums certain usergroups are allowed to view.
I wish you luck with all this legal bullshit.