For what it is worth, my university almost shut my computer off from the world due to the fact that while in ultrapeer mode, the large amounts of icmp packets set off their intrusion detection system (IDS). Not that it was doing any harm to anyone. Mind you, being a computer in an academic lab, the files were academic related and not files that would have offended the so called copyright ownership of certain larger media companies. But it does point out the fact that ultrapeer mode may perhaps be more visible if that is an issue for you.