Oh yeah....

"If the IP address is in the west":

Assuming:

IP address is logged especially if it is DHCP - if this is released to authorities, and even if the ISP actually holds onto the data for very long (xs4all is good!)

If the Internet Cafe keeps records of who uses computers (I've been in several in london and handed over no more than my money to sit down).

Here is a good one:

Someone robs a bank and uses a legal hand gun - leaves it at the scene. What are the chances that the hand gun was actually theirs? Oh thats right - criminals - that is the people we are trying to catch here - hide their tracks.

IP address are pointless. Bot networks, bouncers, free dial up internet (0845)... it easy to make yourself anonymous if you are trying to.

Bit like those pesky ID cards - watch out for the Criminal robbing the bank with his ID card incase he gets stop..... oh yeah right.