Non-payer

Always wondered about that due to home ADSL and a lot of office XDSL being allocated IP addresses dynamically i.e. whenever the router reboots you get a new IP address.

So according to my very limited understanding of this you could just reboot your router then log in with a new user ID and email address?

Been a long, long time since was lumbered with a dynamic IP but generally it'll allocate from a smallish pool based on which DHCP server is closest to you in the ISP's network topology. So you might not get the same IP, but you'll probably get one with only the few least-significant bits differing at most: not hard to spot. Many ISPs these days seem to dole out the same ISP to the same phone line/cable modem MAC for months at a time anyway. And bear in mind that, presuming you're using a fairly standard log format, you're looking for an IP address (or bits thereof)/user-agent tuple rather than just the address, which can be used to eliminate some proportion of innocent bystanders.