Its not. Just each username is suspended. Tech probs with banning IPs (especially dynamic ones). It just means the COs have to manually ban it each time it uses a username. A real nause for them seeing how it happens every 48 hours.
I'd recommend ringing it up (see link on first post) each time it logs in or posts. Even better, ring her mum, ask for Phyllis. Hopefully it'll get the message and fuck off from here for good.