No, using PG2 does you no good whatsoever. It's false sense of security. By the time it blocks a connection, they already have all the info they need. Namely your IP, and what torrent it's associated with. It's a pure waste of your computer's resources.
But surely your IP and the torrent isn't enough alone? Don't they have to prove that you are sharing that file?
I know that in previous cases, the "evidence" has been files which the anti-p2p people have downloaded from the accused persons computer. They may be able to SEE you in the swarm, but if they can't get files from you, they can't prove that you were sharing.
I also don't understand the "false sense of security" argument... it's only a bad thing if you act differently or recklessly because you think you are protected. If you have PG2 running, *and* you act carefully (i.e. sticking away from brand new movies on public trackers etc) I don't see how that isn't giving you a small amount of extra security.
Also, going back to the numbers thing. If you were silly enough to download Iron Man from the pirate bay, you'd see there have been >10,000 downloads. Obviously, anti-p2p people can't chase everyone so do you not think that making things even 5% more difficult, *still* reduces your odds?
And currently PG2 is using 3.2mb of my 4Gb of RAM.. I don't think it's slowing me down too much.
Any thoughts?