You are *NOT* anonymous on the Internet. Any organization/person can go to court and demand from your ISP to disclose the full details (name, address, etc) of the person who is using the service at IP x.x.x.x during time xx:xx:xx TZ at date xx-xx-xxxx. Also publicly stating that you are doing things like that is probably not the smartest thing. To 'resolve' things like this, either don't use it, or properly firewall it away. Also note that most 'agencies' looking for violations don't have a clue about IPv6. As for people who don't realize that when they are doing something illegal, that that is illegal, well, we are not lawyers, and we can't introduce a big banner on their screens saying what is and what is not illegal. As such, it is the users problem to make sure they are not doing anything illegal, we are not their babysitters.

You can launch java with and force an IPv4 in the tracker announce address, but there is no guarantee it will shut down IPv6 DHT and as far as I (poorly) understand v6 announcements can be sent over V4 so you can't even filter it out. With Azureus/Vuze 4 the developers have decided to force this behaviour whether you want it or not.