Procrustes Stretched
This place is nothing without the membership.
well first off, an IP does not mean you can find anyone. In fact, chances are low.
wrong
If someone uses a public computer, or even a computer on a shared home network, like if they have several roommates all sharing the same router, you can't track down one person.
wrong again. many routers track MAC addresses and upstream ISPs log *everything* and they do turn it over quickly with subponea. also, if forensics investigators get their hands on any of the machines invovled they can quickly say whether any of the machines performed the illegal activity as most people are clueless about how to proper cover their tracks.