what about feature to add in W:A, where are posibilty to recognize w:a players using mac, instated of ip? it could resolve problem with dynamic ip.. for example: someone who breaks several rules can be baned form team17 for a while... :)

Two problems with this:

1. MAC addresses are easy to change
2. I'm not sure it's possible to get the MAC address of someone you're connected to over the internet

MAC addressing is on a lower networking layer, and it changes from hop to hop, ie the MAC address of all packets is that of the device that routed it to your PC, not that which originally sent it.