I'd recommend using them on a public tracker because when I used to use it, MediaSentry would be on the blocklist more than a couple of times.
If you're using a private tracker however, I'd recommend against it. Agents undercover are not going to be stupid enough to use their anti-piracy company's IP address; they'd probably get spotted and banned. So PG2 would have no affect, except for having many harmless addresses blocked.
And the less programs you're running in the background, the better.
