Just wait until someone gets arrested.

The technology will change once again to get around the legalese. Also of note, Japan has very strong anti-wiretapping laws[0] that prohibit carriers and other providers from port blocking, tapping or redirecting packets -- the only presumable legal way for these associations to check on downloaders would be to hold illegal content themselves and wait for a Japanese IP address to connect.

[0] http://ja.wikipedia.org/wiki/%E9%80%9A%E4%BF%A1%E3%81%AE%E7%...