It seems that one of the challenges of these services is that in order to avoid the copyright goons everyone you know, even those folks you only know by some IRC handle, have to be willing to go to jail for you. Because otherwise one of them will get turned, they will then be pressured to get you to indict yourself. This is how it worked against Anonymous, and how it works on most disobedience rings (civil or otherwise). One of your friends will share with you a folder that has copyrighted material in it, once they are sure you have accessed it they will re-iterate that some (or all) of the material there is copyrighted. At this point the most common thing that happens is that thinking they are 'safe', someone will say something stupid like 'don't worry, its our secret' or something like that.
And almost simultaneously the door will explode open as the SWAT guys come in and put them in cuffs and read you your rights. All because someone you thought you knew, was unwilling to spend time in jail rather than help the FBI with their investigation.
Law enforcement has a number of tools (many dubious like the CFAA) which they can employ against you, and they will.
The best you can hope to achieve is to keep a solid (and I mean solid, no slip ups anywhere) public front of respecting the copyright holders rights and your willingness to protect them. Otherwise you will be served papers to decrypt other buckets and you will be sent to jail for contempt if you do not facilitate rooting out copyright infringement on your service. Not even keeping your servers and company in a foreign country will help unless it is a country which doesn't care about its relationship with the US.