PG2, as well as PeerBlock are decent, and the later comes built in with a block for the particular group Toei has serving these letters to IPs (not sure about peer guardian... has that even been supported in the past year? PeerBlock is a spin off project since PG2 wasn't working with vista or 7, but does the same thing), for the most part DDLs are safer. Provided you know who's posting the links. Your safest bet is direct connect programs like IRC or AIM that create private one on one connections, making it a lot harder to trace.
From talking to one of my friends over at TOEI's LA office, it seems like they're not going any further than C&D letters for now, or if they are, they haven't informed their localization offices of such, so you're free to take the risk yourself as you see fit.